Faience became sophisticated and produced on a large scale, using moulds as well modelling, and later also throwing on the wheel. Several methods of glazing were developed, but colours remained largely limited to a range in the blue-green spectrum. On the Greek island of Santorini are some of the earliest finds created by the Minoans dating to the third millennium BCE, with the original settlement at Akrotiri dating to the fourth millennium BCE;  excavation work continues at the principal archaeological site of Akrotiri.
Some of the excavated homes contain huge ceramic storage jars known as pithoi. Ancient Greek and Etruscan ceramics are renowned for their figurative painting, especially in the black-figure and red-figure styles. Moulded Greek terracotta figurines , especially those from Tanagra , were small figures, often religious but later including many of everyday genre figures, apparently used purely for decoration. Ancient Roman pottery , such as Samian ware , was rarely as fine, and largely copied shapes from metalwork, but was produced in enormous quantities, and is found all over Europe and the Middle East, and beyond.
Monte Testaccio is a waste mound in Rome made almost entirely of broken amphorae used for transporting and storing liquids and other products. Few vessels of great artistic interest have survived, but there are very many small figures, often incorporated into oil lamps or similar objects, and often with religious or erotic themes or both together — a Roman speciality. The Romans generally did not leave grave goods, the best source of ancient pottery, but even so they do not seem to have had much in the way of luxury pottery, unlike Roman glass , which the elite used with gold or silver tableware.
Ceramic Raw Materials
The more expensive pottery tended to use relief decoration, often moulded, rather than paint. Especially in the Eastern Empire, local traditions continued, hybridizing with Roman styles to varying extents. Tin-glazed pottery, or faience, originated in Iraq in the 9th century, from where it spread to Egypt, Persia and Spain before reaching Italy in the Renaissance , Holland in the 16th century and England , France and other European countries shortly after. By the High Middle Ages the Hispano-Moresque ware of Al-Andaluz was the most sophisticated pottery being produced in Europe, with elaborate decoration.
It introduced tin-glazing to Europe, which was developed in the Italian Renaissance in maiolica. Tin-glazed pottery was taken up in the Netherlands from the 16th to the 18th centuries, the potters making household, decorative pieces and tiles in vast numbers,  usually with blue painting on a white ground.
Dutch potters took tin-glazed pottery to the British Isles, where it was made between about and The development of white, or near white, firing bodies in Europe from the late 18th century, such as Creamware by Josiah Wedgwood and porcelain , reduced the demand for Delftware, faience and majolica. Today, tin oxide usage in glazes finds limited use in conjunction with other, lower cost opacifying agents, although it is generally restricted to specialist low temperature applications and use by studio potters,   including Picasso who produced pottery using tin glazes.
Within a few decades, porcelain factories sprung up at Nymphenburg in Bavaria and Capodimonte in Naples and many other places, often financed by a local ruler. Soft-paste porcelain was made at Rouen in the s, but the first important production was at St. Cloud , letters-patent being granted in In a patent was taken out on the first bone china , subsequently perfected by Josiah Spode. Porcelain was ideally suited to the energetic Rococo curves of the day. The products of these early decades of European porcelain are generally the most highly regarded, and expensive.
Like other leading modelers, they trained as sculptors and produced models from which moulds were taken. By the end of the 18th century owning porcelain tableware and decorative objects had become obligatory among the prosperous middle-classes of Europe, and there were factories in most countries, many of which are still producing. As well as tableware, early European porcelain revived the taste for purely decorative figures of people or animals, which had also been a feature of several ancient cultures, often as grave goods.
These were still being produced in China as blanc de Chine religious figures, many of which had reached Europe. European figures were almost entirely secular, and soon brightly and brilliantly painted, often in groups with a modelled setting, and a strong narrative element see picture.
From the 17th century, Stoke-on-Trent in North Staffordshire emerged as a major centre of pottery making. The local presence of abundant supplies of coal and suitable clay for earthenware production led to the early but at first limited development of the local pottery industry. The construction of the Trent and Mersey Canal allowed the easy transportation of china clay from Cornwall together with other materials and facilitated the production of creamware and bone china.
Other production centres had a lead in the production of high quality wares but the preeminence of North Staffordshire was brought about by methodical and detailed research and a willingness to experiment carried out over many years, initially by one man, Josiah Wedgwood. His lead was followed by other local potters, scientists and engineers. Wedgwood is credited with the industrialization of the manufacture of pottery. His work was of very high quality: when visiting his workshop, if he saw an offending vessel that failed to meet with his standards, he would smash it with his stick, exclaiming, "This will not do for Josiah Wedgwood!
His unique glazes began to distinguish his wares from anything else on the market. His matt finish jasperware in two colours was highly suitable for the Neoclassicism of the end of the century, imitating the effects of Ancient Roman carved gemstone cameos like the Gemma Augustea , or the cameo glass Portland Vase , of which Wedgwood produced copies. He also is credited with perfecting transfer-printing , first developed in England about By the end of the century this had largely replaced hand-painting for complex designs, except at the luxury end of the market, and the vast majority of the world's decorated pottery uses versions of the technique to the present day.
The perfecting of underglaze transfer printing is widely credited to Josiah Spode the first. The process had been used as a development from the processes used in book printing, and early paper quality made a very refined detail in the design incapable of reproduction, so early print patterns were rather lacking in subtltey of tonal variation. The development of machine made thinner printing papers around allowed the engravers to use a much wider variety of tonal techniques which became capable of being reproduced on the ware, much more successfully.
Far from perfecting underglaze print Wedgwood was persuaded by his painters not to adopt underglaze printing until it became evident that Mr Spode was taking away his business through competitive pricing for a much more heavily decorated high quality product. Studio pottery is made by artists working alone or in small groups, producing unique items or short runs, typically with all stages of manufacture carried out by one individual.
Bernard Leach — established a style of pottery influenced by Far-Eastern and medieval English forms. After briefly experimenting with earthenware, he turned to stoneware fired to high temperatures in large oil- or wood-burning kilns. This style dominated British studio pottery in the midth-century.
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The Austrian refugee Lucie Rie — has been regarded as essentially a modernist who experimented with new glaze effects on often brightly coloured bowls and bottles. Hans Coper — produced non-functional, sculptural and unglazed pieces. After the Second World War, studio pottery in Britain was encouraged by the wartime ban on decorating manufactured pottery and the modernist spirit of the Festival of Britain.
The simple, functional designs chimed in with the modernist ethos. Several potteries were formed in response to this fifties boom, and this style of studio pottery remained popular into the nineteen-seventies. Fritsch was one of a group of outstanding ceramicists who emerged from the Royal College of Art at that time. Fritschs' ceramic vessels broke away from traditional methods and she developed a hand built flattened coil technique in stoneware smoothed and refined into accurately profiled forms. They are then hand painted with dry matt slips, in colours unusual for ceramics.
In a pottery was founded in Vienna. An important collection of antique porcelain is preserved in the Russian Museum of Ceramics. The people in North, Central, and South America continents had a wide variety of pottery traditions before Europeans arrived. Some archaeologists believe that ceramics know-how found its way by sea to Mesoamerica , the second great cradle of civilization in the Americas.
During the same period, another culture developed on the southern coast of Peru, in the area called Paracas. In the early stage of Nazca ceramics, potters painted realistic characters and landscapes. The Maya were relative latecomers to ceramic development, as their ceramic arts flourished in the Maya Classic Period , or the 2nd to 10th century. One important site in southern Belize is known as Lubaantun , that boasts particularly detailed and prolific works. As evidence of the extent to which these ceramic art works were prized, many specimens traced to Lubaantun have been found at distant Maya sites in Honduras and Guatemala.
Nampeyo  and her relatives created pottery that became highly sought after beginning in the early 20th century. Pueblo tribes in the state of New Mexico have styles distinctive to each of the various pueblos villages. In the early 20th century Martinez and her husband Julian rediscovered the method of creating traditional San Ildefonso Pueblo Black-on Black pottery. Mexican ceramics are an ancient tradition. Precolumbian potters built up their wares with pinching, coiling, or hammer-an-anvil methods and, instead of using glaze, burnished their pots.
There is a strong tradition of studio artists working in ceramics in the United States. It had a period of growth in the s and continues to present times. Many fine art, craft, and contemporary art museums have pieces in their permanent collections. Beatrice Wood was an American artist and studio potter located in Ojai, California. She developed a unique form of luster-glaze technique, and was active from the s to her death in at years old. Robert Arneson created larger sculptural work, in an abstracted representational style. There are ceramics arts departments at many colleges, universities, and fine arts institutes in the United States.
Pottery in Sub-Saharan Africa is traditionally made by coiling and is fired at low temperature. The figurines of the ancient Nok culture , whose function remains unclear, are an example of high-quality figural work, found in many cultures, such as the Benin of Nigeria. Ladi Kwali , a Nigerian potter who worked in the Gwari tradition, made large pots decorated with incised patterns.
Her work is an interesting hybrid of traditional African with western studio pottery. Magdalene Odundo is a Kenyan -born British studio potter whose ceramics are hand built and burnished. A ceramics museum is a museum wholly or largely devoted to ceramics , normally ceramic artworks, whose collections may include glass and enamel as well, but will usually concentrate on pottery , including porcelain.
Most national ceramics collections are in a more general museum covering all the arts , or just the decorative arts , but there are a number of specialized ceramics museums, some concentrating on the production of just one country, region or manufacturer. Others have international collections, which may concentrate on ceramics from Europe or East Asia, or have global coverage.
In Asian and Islamic countries ceramics are usually a strong feature of general and national museums. Outstanding major ceramics collections in general museums include The Palace Museum, Beijing , with , pieces,  and the National Palace Museum in Taipei city , Taiwan 25, pieces ;  both are mostly derived from the Chinese Imperial collection, and are almost entirely of pieces from China. A funerary urn in the shape of a "bat god" or a jaguar, from Oaxaca , Mexico, dated to — CE. Height: 9. From Wikipedia, the free encyclopedia.
Main articles: Earthenware , Stoneware , Porcelain , and Bone china.
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Main article: China painting. Main article: Slipware. Main article: Terra sigillata. Main article: Studio pottery. Main article: Tile. Main article: Figurine. Main article: Tableware. Main article: Pre-Pottery Neolithic. Main article: Chinese ceramics. Main article: Japanese ceramics. Main article: Korean pottery and porcelain. Main article: Islamic pottery. Main article: Tin-glazed pottery. Main article: Native American pottery. See also: Category:American potters and Face jug.
Main article: Ceramics museum. Ancient Egyptian. Arts portal History portal. Archived from the original on 2 June Retrieved 5 January Thomasen, C. Masonry: Materials, Design, Construction and Maintenance. Lee, W. Carty, J. Euro Ceramics V. Trans Tech Publications , Switzerland,, p. Singer, S. Quote: "The lighter pieces that are glazed may also be termed 'terracotta.
Retrieved 19 March Asian Ceramics. November,, p. As with stoneware, the body becomes vitrified; which means the body fuses, becomes nonabsorbent, and very strong. Unlike stoneware, china becomes very white and translucent. China painting. Contemporary tableware. London: A. New York: Harry N.
Harvard University Press. National Museum of China. June Proceedings of the National Academy of Sciences. Bibcode : PNAS.. Archived from the original on 2 January Retrieved 2 January USA Today. Chinese Ceramics. The New Standard Guide. Thames and Hudson, London. Archived from the original on 3 March Smithsonian Institution.
Archived from the original on 1 September Retrieved 2 August Muqarnas: Annual on Islamic Art and Architecture. Brill Academic Publishers. Mason , p. Borax Consolidated Limited. Orientalism in Early Modern France. Oxford: Berg Publishing, p. The pilgrim art. Cultures of porcelain in world history. University of California Press, p. Cambridge University Press, p.
Archived from the original on 24 November Retrieved 24 July Retrieved 25 July The Florida Times-Union. Retrieved 12 May Although foreign producers will endeavor to increase their future scrap exports to the U. Good quality scrap mica is delaminated and fabricated into mica paper for the electronic and electrical industries.
The remaining scrap and flake is processed into ground mica for various industrial end uses, with a significant quantity of good quality scrap being delaminated for fabrication into reconstituted mica products. In , scrap and flake mica were processed by 20 companies operating 22 grinding plants in 14 states.
There are approximately 20 flake mica producers in the U. Sheet mica is used in the manufacture of vacuum tubes, capacitors, and other electrical and nonelectrical items. Muscovite block and film was consumed by 17 companies in 8 states during Splittings were fabricated into built-up mica products by 13 companies in 9 states.
Six companies accounted for almost four-fifths of total consumption. No immediate raw-material source problem is seen. Further growth in consumption is likely to be proportional to the rate of building construction. Crude perlite was produced by 12 companies at 14 mines in 7 states. Natural quartz crystal demand is predicted to increase domestically at a maximum annual growth rate of 0. Substitution of synthetic manufactured quartz for natural quartz has lowered U. Practically all electronic-grade natural quartz is processed into finished crystals for electronic frequency-control or selection equipment.
A very small quantity is used for prisms, wedges, lenses, and other optical. Raw quartz crystal in was consumed by 26 cutters in 12 states. New soda ash production facilities are dependent entirely on natural sodium carbonate minerals rather than salt.
Products Applications Alone Are Clay Ceramics Than More Materials Raw
Some solvay plants have been ordered to close because their effluent could not meet new standards set by environmental protection authorities. Of the total sodium carbonate produced in the U. Sodium carbonate is derived from natural sources by four companies. Five companies produce sodium carbonate from salt. Talc-group minerals demand is forecast to grow at between 2.
Domestic resources will be more than adequate to meet domestic needs. Talc, soapstone, and pyrophyllite are consumed by many firms in all parts of the country. Crude output was processed by about 40 grinders, mostly in the same locations. Vermiculite demand is predicted to increase domestically at an annual rate of 3.
In an expanded form, vermiculite is important commercially as a concrete aggregate and as a thermal insulating material, but faces competition from other low-cost products with similar properties such as perlite and pumice. Improvements to minimize the treatment losses in fine fractions or to provide a market for fine-size vermiculite could enhance the competitive position of vermiculite.
Uses for vermiculite are many; it is a loose-fill insulating medium with or without the addition of a binder. Mixed with gypsum plaster, vermiculite forms an acoustical medium for sound absorption; with portland cement, a lightweight concrete results. Gypsum, clay, asbestos, and suitable cements are added to vermiculite to produce a fireproofing medium that can be applied to building structures. Agricultural uses are as soil conditioner, a plant growing medium, and a packing material for nursery stock.
One company predominates in exfoliating. In all, 25 companies operate 52 exfoliating plants in 33 states. The production total was about 10 million tons, which is comparable with the nonferrous metals. Moreover, as first pointed out by Houwink 3 , the volume of plastics being produced is rapidly approaching that of all metals. The production of key plastics by type, based on data by Jenest 5 is shown in Table 7. The financial characteristics of the plastics industry have been well summarized by Jenest 5. Two aspects having a materials orientation are worth noting here.
The first is the price-volume relationship. The line, as drawn, has a slope of -3, indicating the extreme sensitivity of sales volume to selling price. Certain plastics, notably Nylon 6 and fluorocarbons are sold in greater quantities than would be indicated by their price alone. Secondly, in comparing cost of plastics with metals, the large difference in density often requires that costs be expressed in price per unit volume.
Thus, the polycarbonate is more than competitive with zinc in applications where its properties are adequate, particularly since the polycarbonate is easier to fabricate. The major types of plastics-fabrication processes in use today 5 are shown in Table 7. One significant recent trend in plastics fabrication is that major end-users of plastics parts, such as the appliance and automotive industries, are undertaking the fabrication themselves with large and sophisticated facilities. Another trend is the increasing attention being given to the disposal of post-consumer plastic wastes. Reuse and recycling possibilities are currently receiving greater attention, as well as disposal via energy generation as fuel.
Jenest, The Plastics Industry , A. Little Co. Sources: U.
Little, Inc. Plastics as used for engineering purposes are usefully considered in terms of two major classes—engineering plastics and composition. Engineering plastic materials are specific polymers that have a combination of properties—strength, temperature resistance, solvent resistance, creep resistance, etc. Such materials are nylon, polyacetals, teflon, polycarbonates, polyphenylene oxide, etc.
Composites—as the name implies—are mixtures of polymers or of polymers and inorganic materials in physical forms and ratios designed to develop specific properties:. Fiber-reinforced thermoplastics and thermosets : Glass fibers in the form of chopped fiber, continuous roving, and cloth are used to reinforce plastics of both thermoset types: polyester and epoxy, as well as in thermoplastics such as polyethylene, polypropylene, polystyrene, nylon, etc.
Rubber-reinforced high impact polymers : The toughness of brittle plastics such as polystyrene, polymethyl-methacrylates, and PVC can be enhanced by blending the plastic with an unvulcanized rubber elastomer. Since any two polymers are typically incompatible, a rather complex two-phase morphology results. Ease of fabrication plus enhanced properties are achieved. A sandwich made of two sheets of metal with an inner core of a plastic having high internal friction is an efficient sound deadener.
As with a metal skin on a foamed plastic core, sandwich panels provide a high section modulus, thermal insulation, gas barrier, and light weight. Plastics in concrete : The brittleness of concrete can be overcome to some extent by incorporating fibers such as nylon and glass, polyethylene particles, or latex. In its utilization of technical manpower, the plastics industry has traditionally employed the following professionals in the role of materials scientists and engineers:. Finally, in considering long-term ecological aspects of the plastics industry, it is important to recall that the major raw material in plastics has shifted from cellulose to natural gas and petroleum.
The trend away from cellulose as a base has been largely an economic one arising from the cost of raw materials and the high capital investment involved in converting natural cellulose to moldable plastics. It appears unlikely at the present time that, in the absence of legislation based on ecological considerations or a dramatic change in price or availability of petroleum, the plastics industry will expand the use of cellulose derivatives, cellophane film, and chemically-treated wood.
Nevertheless, it is worth noting that the greater use of cellulose could have the following effects on ecology in addition to conserving petroleum:. Newsprint and waste cotton fabric might be recycled to become a raw-material base for plastics. Cellulose-rich plastics might be more biodegradable than hydrocarbon or chlorohydrocarbon polymers. At the same time, other ecological aspects might be worsened such as greater use of insecticides and fertilizer in the growing of cotton or wood as a raw material for plastics.
In a very real sense, no industry is independent of materials to construct or produce its products—whether goods or services. Thus, the limited number of industries described in this section have been selected for attention because they illustrate the different ways in which materials enter into the manufacturing process and they also represent key sectors of. The order in which they are discussed—electronics, electric lamps, containers, automobiles, and construction—corresponds both to an increasing scale of the product involved, and to a shift of emphasis from electrical to mechanical properties in designing materials for the product.
Illustration of the Role of Materials Science and Engineering : Even before the invention of the transistor in July , electronics was a substantial industry with an emerging area of manufacture and application of several semiconductors. Thus, knowledge of the science and technology of both silicon and germanium had become rather advanced both in this country and abroad.
However, the announcement of the first transistor by Bardeen and Brattain at Bell Telephone Laboratories initiated a new era unique in the interplay it engendered between science and technology and between materials and device concepts, a phenomenon that has characterized the industry now for a quarter of a century. This interplay has been complex because of the great number of device requirements and the variations of materials, designs, and processes to be controlled to widely different parameters and to close tolerances.
The understanding of the solid state that has come as a byproduct of these developments in the electronics industry may turn out to be an even greater contribution. Because of this general importance, it is useful to examine some of the technical developments that have led to this understanding. In the same year that the invention of the transistor was announced, and in the same Laboratories, Teal and Little began experiments to grow large single crystals of high structural perfection in germanium by a pulling technique to test their idea that grain boundaries and other defects normally present masked the desirable electronic properties.
Buehler and Teal also improved the purity by repeated recrystallization methods. These single crystals had, as well as improved uniformity, such strikingly new and different properties in contrast to polycrystalline germanium as lifetimes of minority carriers 20— times greater and mobilities 3—4 times greater. Analogous success was attained in early with preparing single crystals of silicon. With the development of useful devices, the demands for these high-purity materials increased sharply.
Satisfaction of these demands was greatly simplified, in , when Pfann developed a method particularly appropriate for production—the process of zone refining—in which a. The first transistor was an experimental triumph in that it was not really clear what processes were actually taking place at the all-important conductor point brought into contact with the semiconductor material. However, during the next year , Shockley analyzed the rectification in p-n junctions and showed the possibility of obtaining transistor action using p-n junctions in bulk material. In response to this development, Sparks devised a unique method for preparing p-n junctions by modifying the Teal-Little crystal-pulling apparatus to allow controlled addition of impurities during crystal growth; the resulting new kind of transistor was first prepared in These single crystal materials not only provided a revolutionary electronic device, but also gave media sufficiently perfect to test the validity of solid-state theories, and so further their development.
The same basic techniques of making multiple junction structures was applied later to silicon, then a more difficult material to work with than germanium, and was the exclusive method for making commercial silicon transistors, beginning in , for several years. In , an alloying technique was used successfully to prepare single p-n junctions in germanium by Hall and Dunlap of General Electric, and Saby prepared p-n-p transistors in the same manner.
Application of the alloying technique to silicon was delayed until an improved silicon purification technique, floating-zone refining, was developed by Theuerer and independently by Emeis and Keck. However, other experimenters conceived the idea of setting up a stable molten zone in a vertical rod of material by virtue of surface tension, which meant that zone purification could then be extended to silicon. Diffusion processes rapidly displaced alloying techniques and alloyed silicon transistors never became as significant as in the earlier application to germanium.
Engineering demands to make semiconductor devices operate at higher and higher frequencies stimulated work on materials processes that would provide the smaller and smaller geometries that were required. Following original work of Fuller at the Bell Telephone Laboratories and Dunlap at General Electric, the Bell Telephone Laboratories published in early descriptions of both germanium and silicon transistors made by diffusion techniques. The combination of diffusion technology with the earlier processes, and the device designs made possible by the new approach, produced a wide variety of innovative devices of increasing performance.
During the next year or so, two particular milestones in materials technology were passed which were of special importance in the light of later events: a the observation by Frosch that a thermally-grown oxide on silicon impeded the diffusion of certain impurities, coupled with photographic masking against etching, provided a powerful tool for silicon processing; and b the studies by Dash of dislocations in silicon resulted in developing methods for growing silicon single crystals with essentially no.
In June , the Bell Laboratories announced a new method of fabricating transistors using epitaxial single crystals grown from the gas phase with controlled impurity levels. The advantages of this method broke the year-old requirement of having to start with a high-purity crystal and then add impurities in a controlled manner to obtain the characteristics required in the device. In , Kilby Texas Instruments fabricated the first integrated circuit.
This concept made possible the implementation of many functions on a single chip of silicon, viz. Key modifications to the technology already developed for discrete devices included diffusion through the epitaxial layer of an integrated circuit to provide the high resistance of a reversed-bias p-n junction as isolation for adjacent devices and the MOS concept. The field-effect device proposed originally by Shockley, and now called the MOS transistor—for metal-oxide-semiconductor transistor— became possible because of advances in materials surface-treatment techniques; for some applications, the MOS technology, because of its low-power requirements, high-packing densities, fewer processing operations, and other characteristics, turns out to be markedly superior to the conventional bipolar technology.
The preceding discussion provides an illustrative example of some of the significant advances made in electronic materials. Nevertheless, the outline does demonstrate the tremendous degree to which the materials technologist has achieved control of electronic materials: for example, the extremes of purity; the control over doping at very low levels; the variety of techniques for creating junction structures by introducing impurities at exactly the right positions in the lattice and with very close tolerances on their positions and concentration profiles; the intricate combinations of single-crystal regions in device structures; crystals of high structural perfection; crystal-growth techniques.
An additional, but especially important, point is the cross-fertilization effect for research on other classes of materials. For instance, the extended study of semiconductor crystals has increased understanding of the mechanical behavior of structural materials; dislocations were first seen in semiconductor materials, and much of our direct knowledge of defects in solids was obtained initially from studying these materials.
The creation of dislocation-free crystals was of great significance for the scientist and engineer working with nonelectronic materials. At the time of the invention of the transistor, solid-state physics was a minor part of physics, but now it is the largest single subfield of physics.
The present sophisticated understanding of the electronic structure of solids grew from the semiconductor work, first on carrier behavior and then followed by the study of band structure. As indicated by the sequence of dates, achievement after achievement crowded one upon the other, somewhat reminiscent of the urgency of wartime development of technology. During the decade when the principal production consisted of discrete devices, process gave way to process in such quick succession that manufacturers hesitated to invest in technically possible mass-production equipment because it might become obsolete in literally a few months.
Although the normal research communication media of journal publications and seminars continued to be used, the visit and the telephone seemed to have become the mode of exchange among scientists, metallurgists, engineers, and the many varieties of production people.
In this mode, it is often difficult to determine in which of the conventional disciplines a given individual is acting. An additional feature was that the sequence of invention often was reversed from the older concept of first conceiving the device and then developing the material which makes it possible; in many instances, it was research on semiconductor materials that laid the basis for a new device design. Some Characteristics of the Electronics Industry : Figure 7.
These particular components can be regarded as the major ones in the industry. The shapes of the curves shown in Figure 7. Its principal predecessor, receiving tubes, is past maturity and is now steadily declining. It is interesting to note that the power and special purpose tubes, which are not as easily replaced by semiconductor devices or integrated circuits, still maintain an upward trend. For the TV picture-tube curve, the unusual shape arises largely from the superposition of two curves—black and white TV picture tubes and color TV picture tubes.
In , total shipments were about 9 million tubes 3 million black and white and 7 million color , and the ratio in per-tube value had declined to about 4. Six classes of components appear to be holding essentially steady growth. These are capacitors, resistors, power and special purpose tubes, connectors, transformers and reactors , and relays. The most spectacular curve in Figure 7. Over this same period of five years, the whole integrated circuit class averaged 23 percent growth per year. Such a measure is indicated in Figure 7. For reference, the analogous consumer prize index is also plotted to provide a measure of inflation over the period.
A significant general characteristic is the stiffening of per-unit values from to , when curves tend to change slope toward a positive direction. As in the previous figure, the most distinctive behavior is exhibited by integrated circuits; assuming that this sector branches off from the parent semiconductor devices in , the equivalent per-unit value declined by to less than one-tenth that of Processing of Semiconductor Materials : The most commonly used semiconductor material in the electronics industry is silicon.
Next to oxygen as the most abundant element, silicon makes up about one-fourth of the crust of the earth. Not found in elemental form, it occurs chiefly as the oxide, silica SiO 2 , and as various silicates in such familiar forms as sand, quartz, rock crystal, amethyst, agate, flint, jasper, opal, etc. The characteristics of semiconductor materials that make them useful in electronic devices are profoundly influenced by impurities. Controlled addition of desired impurities dopants in the range from 0.
Accordingly, semiconductor-device technology is focused principally on the controlled doping of materials and the formation of junctions between materials of different impurity concentrations while maintaining a continuous single-crystal structure, without appreciable defects, from one side to the other of each junction.
Diffusion depth and concentration are controlled by the time and temperature of exposure as well as by the chemistry of the dopant gas. To provide insulation between layers or to install a mask against a succeeding diffusion, silicon dioxide is grown on the silicon surface by heating the silicon and exposing it to oxygen or steam.
Selective diffusion or placement of a contact is done by cutting a window through the silicon dioxide layer to get at the semiconductor surface. A similar process is used to etch selectively the metallized layers into the desired configurations of electrical conductors. To make ohmic nonrectifying electrical contacts on the semiconductor material or electrical conductors, aluminum or gold is vacuum-evaporated onto all exposed surfaces. By a succession of steps like those described above, hundreds of microscopic, intricate circuits made up of transistors, diodes, resistors, and capacitors are created on a single 2-inch slice of single-crystal silicon.
The representative processes discussed show how the steps of material processing, device design, circuit design, and system design have been telescoped and blended so that one activity often cannot be distinguished from another. In contrast to these developments in integrated circuitry, which are focused on the task of packing more and more components of the order of 10, into tiny chips of silicon, progress in another branch of silicon technology has led to large discrete devices capable of controlling power in the 10 to Kw range.
The basic element used to perform this function is the thyristor, the semiconductor analog of the gas-discharge thyratron. Thyristors range in size from those used in light dimmers and speed controls for home appliances up to large industrial devices capable of controlling load currents of hundreds of amperes at a thousand volts or more.
They are now being used to rectify and invert power for DC transmission lines at the Mw level. The applications for individual semiconductor devices and integrated circuits are increasingly requiring improvement in the economics of materials usage as well as in performance and reliability. To reduce overall process costs in integrated circuits, the trend is toward 3-inch or larger diameter starting crystals.
Such large diameters are generally achieved by pulling the crystals from quartz crucibles—a technique that serves the larger part of the semiconductor market. For the thyristor, in order to avoid the traces of oxygen found in crystals pulled from quartz, long-lifetime float-zone material is used almost exclusively.
Since the working current that can be controlled by a single thyristor is limited by the diameter of the starting crystals presently available, there is strong incentive for obtaining material of the highest quality in purity and homogeneity together with still larger diameters. Such enhancement in quality may also lead to improved electrical performance in terms of higher voltage ratings. Another illustration of the critical dependence of device performance upon material quality is afforded by the semiconductor detectors used for measuring the energy spectra of nuclear particles.
For example, gamma-detectors consist of germanium p-n junctions, reverse biased, and operated at liquid nitrogen temperature; the absorption of a gamma ray produces a pulse. Until recently, a process extremely difficult to control reliably—the lithium-drift process—had to be invoked as a means of compensating residual impurities in order to obtain the very thick depletion regions that are required for high sensitivity in this device. The new availability of germanium crystals of increased purity large, highly perfect crystals, containing less than 1 part in 10 12 of residual electrically active impurities now make it possible to fabricate the equivalent detector structures without the attendant pitfalls that have beset the lithium-drift process.
The development of material of this unprecedented level of purity depended on new approaches to the detection and elimination of trace impurities, along with significant advances in the techniques of measurement and characterization. The devices in this area include infrared detectors, electroluminescent devices, electron-emission devices, thermoelectric devices, microwave devices, high-power laser windows, and solar cells. The following paragraphs outline some of the key materials features involved in such solid-state products.
Infrared detectors, developed initially for military use, are now finding more general application. The ability of these devices to delineate heat sources makes them useful in such techniques as specialized geographical mapping from aircraft and in clinical detection of human abnormalities. The relevant electronic materials of current importance are indium arsenide, indium antimonide, mercury-cadmium telluride, lead-tin telluride, doped germanium, and doped silicon. Electroluminescent devices utilize the phenomenon that when current is passed in a forward direction across a p-n junction in certain III—V compounds, radiation of optical wavelength sometimes in the infrared is emitted.
Optically, this can be handled by collecting the light incoherently, or a laser beam can be generated along the junction. With the gallium arsenide, which is the LED material, infrared emissions can be produced at room temperatures with an efficiency ranging from 10 to 30 percent. In the case of room-temperature laser diodes which are now made of gallium arsenide and aluminum-gallium arsenide alloy , the critical processing technique is to form a heterojunction to guide the growing optical wave that constitutes the laser beam.
In the optimum process, instead of changing just the nature of the dopant which is measured in only parts per million from one side to the other of the junction, alloys of varying composition are deposited exitaxially to form the heterojunction directly. Electron-emission devices are long familiar in that, for several decades, many different electronic devices have depended on emission of electrons from solid surfaces into vacuum; the most familiar example is the vacuum tube with its heated cathode.
Two newer ways of causing emission at the cathode photoemission and the impact of electrons liberated in this process on further electrodes dynodes causes secondary emission. However, the fundamental problem in all three kinds of emission from surfaces is the same: more emission is desired with the same or less energy. As a result, photomultiplier sensitivity is reaching into the infrared wavelengths of low photon energy.
Thermoelectric generators were originally attractive because of the possibility of high conversion efficiencies in devices which have no moving parts, operate silently, and require little maintenance. Nevertheless, in spite of high cost and low efficiency, numerous important applications have been found where remote, unattended power sources are desirable. Good examples are telephone repeaters, unmanned lighthouses and navigation buoys, space satellites, and scientific instruments on the moon.
In the case of microwave devices, relatively conventional semiconductor units already serve in a number of applications—compact power sources, amplifiers, mixers, and demodulators. More recently, the special property of gallium arsenide, negative differential mobility, has provided a new dimension for the design of microwave devices. Thus, while silicon transistors and trapped-plasma-avalanche-transit-time TRAPPAT oscillators can operate effectively up to about 4 GHz, gallium arsenide devices take over—on the basis of noise, power, bandwidth, and efficiency—up to approximately 30 GHz millimeter waves.
Most gallium arsenide microwave devices require an epitaxial layer 0. Gallium arsenide mixer diodes, while competing with silicon diodes in the 2 to 10 GHz range, are used exclusively in the millimeter range because of superior noise figure and conversion-loss characteristics. Gallium arsenide variable capacitance varactor diodes are employed currently as low-noise, radio-frequency amplifiers and as nonlinear elements in frequency-multiplication channels of digital communication systems; an anticipated new application is for UHF television tuning.
Windows for high-power lasers is an increasingly important application for semiconductor compounds. As greater and greater optical powers are designed into lasers, sometimes many megawatts per square centimeter, interactions between the beam and the material through which it is transmitted occur and failure of the material results. The most common failure mode is thermal fracturing caused by stresses due to thermal gradients, although sometimes the heating causes failure by melting and flowing.
Gallium arsenide, unlike most materials used for windows, resists such failure modes and is. Currently, the wavelength ranges in the infrared of most importance are 2 to 6 microns which is receiving most of the attention and the region around Solar-cell conversion is almost unique among power-generation processes in not causing thermal, gaseous, or particle pollution; consequently, interest in terrestrial application is strong. The major barrier is the high cost of making solar cells; this cost would have to be reduced to about a hundredth or even a thousandth of the present level to make such devices economical.
A possible hope for terrestrial applications is the II—VI semiconductor, cadmium sulfide, in that it can be used in polycrystalline form for solar cells and, because single-crystal technology is not required, may overcome the cost problem. The photovoltaic mechanism in this material is still not well understood, and cells made by a wide variety of techniques all seem to end up with the same properties and operational characteristics. Challenges in the Application of Solid-State Materials : Despite the revolutionary advances that have been made in electronics solid-state materials for use by industry, a number of major problems remain to be resolved.
This section identifies the most critical of these items and indicates the current state of progress. First, there is an urgent need for a better awareness and scientific understanding of the interplay between materials, processing, and device technology. From the point-of-view of materials, this understanding rests heavily on characterization.
It is no longer sufficient to effectively characterize only the starting materials, but also to apply the techniques necessary to measure all the useful attributes of the subsequent device materials throughout the whole manufacturing sequence to the finished product. Although the ultimate reason for applying materials in the electronics industry is to insure effective performance of a device or system in service, too often the thinking that starts with materials research and ends with the operation of the complete system is too compartmentalized.
The materials specialist tries to meet the specifications set by the device expert, who in turn aims to satisfy the circuit designer, who is trying to fit his designs into the subsystem, etc. One procedure that would help make this happen is field-failure reporting and analysis—both during initial development of the device or system and also during commercial operation so as to continue the improvement.
As an example, hybrid systems, the interconnections of similar and different integrated materials subsystems, are currently expensive to fabricate. If batch processing from the raw materials to final assembly were planned as early as the applied research on a given hybrid system and applied during development rather than deferred to pilot production, cost reduction could be expected from lower initial costs through greater yields, and also from lower annual service cost due to increased reliability through better process control.
Some broadly applicable materials areas which require improvements are the following. Research on the effect of so-called nondoping impurities such as oxygen and carbon is needed to clear up many anomalies observed during processing. Thus not enough is known about the theoretical and practical limits of parameters like minority and majority carrier lifetimes as a function of impurity content. Likewise, continued research effort is required on the potentially useful class of amorphous semiconductor materials; without basic understanding of their behavior, device work is likely to be premature and wasteful.
With respect to measurements, more effective methods are needed to determine the chemical purity and electrical characteristics of silicon at all stages of manufacture from raw chemical input through polycrystalline deposition, single crystal growth, and epitaxial deposition. In addition, since the precise measurement of epitaxial-layer thickness and resistivity becomes progressively more difficult as the layers become thinner with advancing device technology, the development of improved rapid, nondestructive methods for characterizing such thin layers would be of substantial value in almost all device developments.
In connection with processing, the preparation of silicon slices by sawing, lapping, and polishing wastes more than half the starting material, and more economic slice-producing methods are needed both for existing and newer applications. For example, to reduce parasitic capacitance thus increasing speed in MOS and bipolar circuitry, an economic supply of very thin silicon on insulating supports is essential.
In the fabrication of materials and devices, much more use could be made of particulate radiative methods for planned introduction of defects—as by ion implantation, sputtering, or electron-gun evaporation. In particular, ion implantation can lead to device characteristics that cannot be achieved with more traditional processes. For the preparation of conducting films, present methods of applying metals in device fabrication, assembly, and packaging are far from satisfactory in that the high-temperature processing steps tend to be destructive to present metal systems.
The phenomenon of ohmic contact remains little understood. Passivation films in the form of improved dielectrics that can be deposited at low temperatures are needed and better film-characterization techniques have to be found for silicon nitride, silicon dioxide, and aluminum oxide. The availability of a truly hermetic low-temperature passivation layer would markedly improve the reliability of semiconductor devices and reduce packaging costs.
As device geometries continue to shrink in size, new processing problems appear. Consequently, imaging technology to transfer mask and other configurations of the order of one micron and below will have to be mastered within a few years. Again, dielectric-silicon interfaces become more critical because impurity and structural defects at these boundaries can dominate the electrical behavior of the device.
Finally, in this listing of processing problems, it is important to point out that packaging and testing before and after packaging account for a large part of total device cost. In this light, research and engineering expended on these tasks is likely to have considerable benefit on both cost and reliability. Turning now to specific devices, the following notes delineate research problems or development areas that require particular attention.
In electron-emission devices, laser applications would benefit by increasing photocathode response at 1. Applied research on III—V alloy systems is a promising approach for the first objective; exploratory materials research is required for the second. To attain the transmission mode required for imaging applications of electron-emission devices, thin crystal layers will have to be grown on a substrate transparent to the incident radiation.
Moreover, a heterojunction technology having a graded alloy region between the substrate and photocathode material has to be developed. In spite of a trend from vacuum electronics to the solid state, a real need persists for a practical cathode capable of operating near room temperature and at high current densities.
To meet such a need would appear to require appropriate research on III—V semiconductors and their alloys. In microwave-device research, improved reliability and higher yield of gallium arsenide devices are important goals. Related to these is an obvious role for better correlation between device performance and materials properties. In thermoelectric research, the major problems common to all telluride alloys are related to their poor mechanical properties and chemical instabilities. Particular difficulty is encountered in fabricating contacts with these alloys at the hot junctions of power-generating thermocouples.
For high-power laser windows, the solution of the failure problem seems to lie in gallium arsenide developments, although this is sufficiently uncertain of success that it should be backed up by exploratory research on other materials. For solar cells, improvements in resistivity and lifetime of the starting silicon are essential. Again, developments of new materials applications may also point the way to significant terrestrial application of these devices. Infrared detectors, in contrast to the above two kinds of devices, operate so close to ideal performance when made correctly that there is no real need for exploratory research on new materials.
Instead, effort is required in the processing to maintain stoichiometry, structural perfection, purity, and chemical homogeneity. Electroluminescent devices, somewhat like infrared detectors, are being made out of satisfactory material, provided that red and orange-yellow-green are acceptable colors; but chemical purity, crystal quality, and limitations of seed substrates need considerably better control.
In magnetic materials, ferrite and ferromagnet properties depend on the nature of inhomogeneity and aggregation, which are inadequately characterized with present techniques. Single-crystal ferrites particularly require better characterization, and fabrication methods for new high-energy-product ferro-magnetic materials are inadequate. In the new magnet-bubble technology, both the fabrication and the characterization of the propagating material are still difficult, and methods of detection of the magnetic bubbles need improvement.
In composite structures, the chief problem is the characterization and understanding of defect and impurity interactions in insulating films and at insulator-metal, insulator-semiconductor, and insulator-insulator interfaces. Particular examples are the influence of hydrogen on silicon dioxide, doping at insulator-semiconductor interfaces, the effect of the metal-insulator interface on metal-insulator-semiconductor device properties, surface charge buildup on insulating layers, lack of integrity of metal and insulating films, measurement of film and interface properties, and metal systems for contacting semiconductors.
Other problems are the development of nonsilicon systems for special purposes and the development of ambient gas and pollutant detectors. Among the needs in inorganic dielectric materials are optical materials for information storage and display, glasses and crystals suitable for communication networks at optical frequencies, improved dielectric materials at microwave frequencies, better dimensional stability in materials for filters and resonant structures at optical and microwave frequencies, adequate substrates for growth of single-crystal films, and higher dielectric-constant and dielectric-strength materials for capacitors.
Finally, in organic dielectric materials, problems lie in uniformity, purity, reduction of voids, compatibility with associated materials, insufficient thermal conductivity, the difficulty of making thin sheets, films, and coatings, microcharacterization, the number of different materials in use, and stability. Stability must be maintained relative to temperature and mechanical changes.
In certain applications, the organic material must also display stability against moisture and oxygen transmission. The devices by which electrical energy is converted into light originated with the carbon-arc lamp. The range of contemporary lamp types includes discharge, fluorescent and photoflash lamps. However, as shown by Table 7. In all of these lamp types, the availability of suitable materials has been critical to the device function. The actual materials involved are few in number and relatively modest in the amounts consumed by the industry see Table 7.
Nevertheless, each performs a unique function, and the. The following paragraphs illustrate some of the material characteristics for each of the major types. It is obvious from the high-technology content of electric lamps, and particularly from the great importance of the relevant materials, that materials scientists and engineers are key people in this field.
There are no specific statistical figures available, but an approximate estimate is that there are — professionally trained people engaged in work closely related to materials technology in the U. In the original carbon-filament lamp, the most critical and obvious materials problem was the provision of the filament itself. In practice, many materials problems had to be solved before the Edison lamp became reliable and reasonable in cost. Thus, a suitably transparent glass had to be fabricated to the desired envelope shape and thickness, by a processing technique suited to high-speed production.
Suitable seals had to be developed so that the electric power could be led to the filament inside the evacuated envelope. The transition to the modern incandescent lamp using a tungsten filament required the development of a material and a powder-metallurgy process that would provide a metal with sufficient ductility so it could be drawn into the fine wire needed for filaments and would retain its integrity over a long operational life. The advantage of the tungsten filaments was in their ability to operate at higher temperatures compared to carbon filaments, resulting in more light in the visible wavelength range per watt-hour of energy expended.
Despite the substantial technological advance with this type of filament, a major limitation on the life of tungsten lamps has been the progressive thinning and eventual failure of the filament due to evaporation of the tungsten at the elevated operating temperature. To overcome this problem, a small amount of a halogen is included inside the lamp envelope. In the so-called iodide or halide cycle, when tungsten is deposited on the lamp envelope, it subsequently chemically combines with the halogen to form a volatile tungsten halide.
These halides, however, are unstable at the higher temperature of the lamp filament. When a molecule of the halide comes into contact with the lamp filament, it is decomposed, redepositing the tungsten on the lamp filament and regenerating free halogen to transport more tungsten from the envelope to the filament. In this way, the envelope wall is kept clean, the filament can be operated again at higher temperatures, and the light output per watt is increased. Today, tungsten-filament incandescent lamps are in extensive use—in particular, for household illumination and for headlamps and other lamps in automobiles.
It is interesting to note that the use of lamps in automobiles has increased from the initial two headlamps and a tail-light to more than 20 lamps per automobile. In discharge lamps, light is produced by electronic transitions in the plasma of an electric arc. A typical high-pressure mercury lamp consists of a watt arc inside a fused-quartz arc tube, which in turn is encased in an outer glass envelope.
A small amount of fluorescent material phosphors is placed on the inside of this envelope in order to convert part of the nm ultraviolet mercury line to visible light. Otherwise, the useful light from a mercury vapor lamp is confined to the four longer wavelengths: ,. In about , the use of an improved envelope material became possible in that research led to new understanding of the factors controlling sintering and then to the development of processes for making aluminum oxide corundum with theoretical density.
The essential discovery was of additives that would reduce grain-boundary mobility, in order to avoid the normal exaggerated grain growth. This discontinuous grain growth results in a porous ceramic which appears white because incident light is scattered. Furthermore, corundum has a much higher melting point than does silica glass, and is much more resistant to attack by alkali metal vapors. Hence, the availability of pore-free alumina allowed for improved lamps as well as other kinds of discharge than those based on mercury.
With a translucent alumina envelope, a sodium vapor-discharge lamp can be made to operate without envelope deterioration at high temperatures and with high sodium pressures. As a result, more atomic transitions in the plasma are excited, and the lamp produces a continuous spectrum of nearly white light it is slightly green-deficient. This advance in materials provided for the first lamp with a continuous spectrum operating at over lumens per watt. This ultraviolet radiation excites fluorescence in phosphors which are coated on the inner surface of the tubular lamp envelope.
The basic phosphor in white fluorescent lamps is calcium halophosphate and various additions are made to modify or control the color of the lamp. Photoflash lamps represent the only important illumination device involving a chemical reaction to heat matter to incandescence. The initial photoflash lamps, developed in Germany, consisted of aluminum foil in an oxygen-filled glass envelope, which could be ignited by an electrically fired primer, so that the foil burned to Al 2 O 3 in about 20—30 milliseconds. Subsequent developments have substituted wire for foil, shredded zirconium and, most recently, shredded hafnium metal for aluminum.
As a result, the light output per unit volume has increased several fold. Meanwhile, the use of these lamps by amateur photographers has increased to the point that more lamps are produced for flash purposes than any other single application. The container industry is the largest segment of the packaging industry; it is defined, for the purposes of this report, as that part of the packaging industry involved in the manufacture of rigid packaging such as cans, bottles, boxes, and tubes. The balance of the packaging industry can be described generally as involved in the manufacture of flexible packaging, such as.
In the following, each of the principal classes of containers—glass, plastic, metal, and paperboard—are reviewed from the point-of-view of materials needs, availability, and recycling characteristics. Glass Containers : The continued growth of glass-container shipments from to is illustrated in Figure 7. The growth rate was about 4. Materials needs in the glass-container industry are conditioned by the fact that, unlike other packaging materials, glass cannot be shipped as an intermediate raw material to a converter for fabrication.
For this reason, the glass producer also produces the container, which is then shipped to the packager for filling, sealing, and shipment. The volume of major raw-material needs Figure 7. Color can be controlled in nearly all glasses by additions in glassmaking of a variety of compounds. Some colors require or are enhanced by oxidation of the coloring agents. Coating of glass containers is quite common and often involves two layers, for example, titanium oxide followed by a lubricious coating such as polyethylene.
Some glass containers such as for aerosols have rather thick coatings of a polymer resin for protection against mechanical damage as well as for aesthetic appeal. Thick opaque or translucent oxide and metallic coatings are sometimes applied to provide desired color effects or light protection. Materials availability does not appear to be a problem for glass containers since, for the present and foreseeable future, there are adequate reserves of the three main ingredients of glass—sand, limestone, and soda ash.
Recycling is readily feasible technically for glass containers, whether as containers or as material, because glass is chemically inert, and does not break down chemically or biologically. However, when bottles and jars are littered, the inertness of the glass means they do not disappear by degradation, but remain visible and can become hazardous wastes. Discarded glass containers do find use as a good aggregate base for construction and in cullet. Examples of direct use of cullet are as a substitute for stone to form a paving material in conjunction with an asphalt binder, and for soil conditioning.
A variety of possibilities for secondary uses of glass are technically feasible; their practicality will depend largely on the development of economical collection methods for the discarded and frequently dispersed containers. Plastic Containers : The principal materials flows and structural features of the plastics-container industry are illustrated in Figure 7.
Plastics have some unique performance characteristics in packaging applications which account for their growth. For example, readily formed blow-molded plastic containers—especially from nonbreakable polyethylene—have essentially replaced glass jugs for many applications. The volume of plastics in packaging of all kinds has grown to 3. This growth and the major end-uses are shown in Table 7.
The materials needs of the industry are derived mainly from the single petroleum and the natural-gas derivatives, ethylene—which is the source of the three major plastics, polyethylene, polyvinyl chloride, and polystyrene see Figure 7. The other major plastic, polypropylene, is obtained from a process by which ethane and propane are produced from natural gas or petroleum fractions. Polyethylene accounted for Polyvinyl chloride PVC usage was 6. The biggest percentage gain in the last five years occurred in PVC, which rose from 4.
Another family of plastics whose use is just beginning to take hold is acrylics—which appear promising for soft-drink bottling. The total volume of plastics consumed by the container industry is expected to double in the period — Materials availability is directly related to the availability of the primary raw materials, natural gas and petroleum reserves, and to competition with their use for energy applications.
For details, see section on Plastics Industry. Recycling of plastics from residential and commercial refuse is little practiced at present. In contrast, plastic wastes are collected commercially by scrap dealers from industry, plastic extruders, converters, molders and fabricators—and can usually be completely recycled. However, polyethylene, which accounts for the bulk of packaging plastics, is virtually worthless as scrap at present.
Metal Containers : The flow of the principal materials—in steel and aluminum—in the metals-packaging industry is shown in Figure 7.lenpokafoser.ga/papiamentu-textbook.php
Chapter 84 - Glass, Pottery and Related Materials
Generally, steel containers are manufactured by independent converters or by packagers from rolled tinplate purchased from the steel industry. The distribution of the output of the industry by end-use and its change with time shown in Table 7. Overall, the ten-year rate of increase in cans consumed — is expected to be 3. The materials needs of the industry are significant in scale as shown by the fact that, in , In , over These relatively flat curves represent an annual growth of about 1.
Materials availability and costs for the industry present some uncertainties for the future. For steel, although there are large quantities of iron ore in the U. The majority of the tin for the making of tin-plate must be imported since there are no large deposits of tin ore in the U. Similarly, large quantities of aluminum and aluminum ores are imported for aluminum cans. For details, see appropriate portions of the section on the Metals Industry.
Recycling of containers has substantial potential, but of the 6. The overwhelming bulk of salvaged materials comes not from post-consumer wastes, but from detinneries who rely on clean clippings from can-production plants for their materials. As with other materials, the economics of collection, sorting, and handling are currently unfavorable for widespread recycling of steel cans.
In the case of aluminum salvage, technologies for complete recycle of canning alloy from post-consumer waste have been developed. Although some such recovery is undertaken, the economics are still uncertain. Paperboard Containers : Paperboard can be divided into five major grades, three of which containerboard, folding boxboard, and foodboard represent the bulk of paperboard containers. Folding boxboard is employed almost exclusively in the manufacture of folding cartons, which are printed, cut, creased, glued, and then shipped flat to the packager who sets up, fills, and seals the carton.
Folding cartons are relatively inexpensive, can be manufactured at high speeds, and are economical relative to transportation and storage costs. The final major grade, foodboard, is used exclusively to manufacture such sanitary paperboard containers as milk cartons, frozen food containers, meat trays, and ice cream cartons. The boards are sized for water resistance and are frequently coated, particularly for applications that require high quality printing.
As more of the primary producers integrate forward into finished products, paperboard and its converted products are increasingly becoming one single industry. The industry is also becoming highly concentrated. Production of Paperboard by Grade Million Tons , — Minor amounts of cotton linters, straw, and bagasse are also used. Pulpwood of suitable species and in the form of logs round-wood or chips is the raw material for woodpulp in paper manufacture. In , This is up from 8. Waste paper in a salable condition for pulping is the second major raw-material source.
The amount of waste paper used varies substantially by grade of product. Materials availability is illustrated by the data in Table 7. The southern states have the greatest concentration of commercial forest area and also the largest volume of timber harvested annually. Recycling is significant in the paper industry, but three-fourths of the waste paper recycled is derived from waste sources other than packaging wastes.
The only paperboard-packaging material which plays a significant role in paper salvage is corrugated containers. An estimated 2. The other paper-packaging materials are usually ignored by salvage operators because corrugated paperboard is more readily available in significant quantities, easily separated, and not as likely to be contaminated as other paper wastes usually are. Recent governmental decisions to encourage recycling by purchasing only paper products that have a specified percentage of recycled paper could induce industry to increase use of waste paper in order to capture this portion of the total market.
However, this shift may increase costs until such time as systems and processes are developed which will increase availability and allow waste fiber to compete with virgin fiber. NOTE: Automotive employment is estimated by the Automobile Manufacturers Association, by assuming that such employment in these industries is in direct proportion to the ratio of automotive shipments to total shipments of the industry. Materials usage in the industry represents a significant fraction of annual U.
A typical four-door sedan contains over a ton and a half of metals, pounds of plastics, pounds of other polymers, and pounds of glass see Table 7. The total consumption of selected metals by the automotive industry in is shown in Table 7. Materials availability is an important question for this materials-intensive industry. The large scale of materials consumption in the automotive industry is a key factor to be taken into account in every product improvement decision. Adding just one pound per vehicle adds some 5, tons to the total materials requirement for the U.
Thus, new materials must have an assured availability in addition to offering cost, performance, and other advantages. Materials conservation, scrap utilization, and recycling in the automotive industry are making substantial progress in their degree of application. The flow of materials with respect to recycling in the industry is described in Figure 7. The latter come in many grades and classifications, numbering as many as 20 or Examples include: No. Solid wastes also arise in the industry from nonproduction materials, i.