Icheon ( Korean : 이천 ; Korean pronunciation: [i.tɕʰʌn] ) is a city in Gyeonggi Province , South Korea.
88-867: Together with Yeoju, Icheon is known as a center of South Korean ceramic manufacturing and is a UNESCO City of Crafts and Folk Art . Other famous local products include peaches and rice . Local institutions of higher learning include Korea Tourism College and Chungkang College of Cultural Industries . Icheon is home to Hynix , the world's second largest memory chip maker. Major building fires occurred on 7 January 2008 and on 29 April 2020 . Neighboring districts include Yeoju , Gwangju , Yongin , and Anseong within Gyeonggi Province, as well as Eumseong County in North Chungcheong Province . The Yeongdong Expressway and Jungbu Naeryuk Expressway pass through Icheon. In 2016,
176-400: A differentiated culture which was earlier thought to be typical Indus Valley civilisation (IVC) culture. Pottery is durable, and fragments, at least, often survive long after artifacts made from less-durable materials have decayed past recognition. Combined with other evidence, the study of pottery artefacts is helpful in the development of theories on the organisation, economic condition and
264-505: A few hundred ohms . The major advantage of these is that they can dissipate a lot of energy, and they self-reset; after the voltage across the device drops below the threshold, its resistance returns to being high. This makes them ideal for surge-protection applications; as there is control over the threshold voltage and energy tolerance, they find use in all sorts of applications. The best demonstration of their ability can be found in electrical substations , where they are employed to protect
352-514: A finer examination of the composition of ceramic artifacts and sherds to determine the source of the material and, through this, the possible manufacturing site. Key criteria are the composition of the clay and the temper used in the manufacture of the article under study: the temper is a material added to the clay during the initial production stage and is used to aid the subsequent drying process. Types of temper include shell pieces, granite fragments, and ground sherd pieces called ' grog '. Temper
440-422: A furnace, a pyroelectric crystal allowed to cool under no applied stress generally builds up a static charge of thousands of volts. Such materials are used in motion sensors , where the tiny rise in temperature from a warm body entering the room is enough to produce a measurable voltage in the crystal. In turn, pyroelectricity is seen most strongly in materials that also display the ferroelectric effect , in which
528-669: A glassy surface, making a vessel less pervious to water. Ceramic artifacts have an important role in archaeology for understanding the culture, technology, and behavior of peoples of the past. They are among the most common artifacts to be found at an archaeological site, generally in the form of small fragments of broken pottery called sherds . The processing of collected sherds can be consistent with two main types of analysis: technical and traditional. The traditional analysis involves sorting ceramic artifacts, sherds, and larger fragments into specific types based on style, composition, manufacturing, and morphology. By creating these typologies, it
616-675: A hard and durable form. The place where such wares are made by a potter is also called a pottery (plural potteries ). The definition of pottery , used by the ASTM International , is "all fired ceramic wares that contain clay when formed, except technical, structural, and refractory products". End applications include tableware , decorative ware , sanitary ware , and in technology and industry such as electrical insulators and laboratory ware. In art history and archaeology , especially of ancient and prehistoric periods, pottery often means only vessels, and sculpted figurines of
704-459: A locality. The main ingredient of the body is clay . Some different types used for pottery include: It is common for clays and other raw materials to be mixed to produce clay bodies suited to specific purposes. Various mineral processing techniques are often utilised before mixing the raw materials, with comminution being effectively universal for non-clay materials. Examples of non-clay materials include: The production of pottery includes
792-416: A more distant connection between groups, such as trade in the same market or even relatively close settlements. Techniques that require more studied replication (i.e., the selection of clay and the fashioning of clay) may indicate a closer connection between peoples, as these methods are usually only transmissible between potters and those otherwise directly involved in production. Such a relationship requires
880-492: A rotation process called "throwing"), slip casting , tape casting (used for making very thin ceramic capacitors), injection molding , dry pressing, and other variations. Many ceramics experts do not consider materials with an amorphous (noncrystalline) character (i.e., glass) to be ceramics, even though glassmaking involves several steps of the ceramic process and its mechanical properties are similar to those of ceramic materials. However, heat treatments can convert glass into
968-581: A rough guide, modern earthenwares are normally fired at temperatures in the range of about 1,000 °C (1,830 °F) to 1,200 °C (2,190 °F); stonewares at between about 1,100 °C (2,010 °F) to 1,300 °C (2,370 °F); and porcelains at between about 1,200 °C (2,190 °F) to 1,400 °C (2,550 °F). Historically, reaching high temperatures was a long-lasting challenge, and earthenware can be fired effectively as low as 600 °C (1,112 °F), achievable in primitive pit firing . The time spent at any particular temperature
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#17327905810441056-434: A semi-crystalline material known as glass-ceramic . Traditional ceramic raw materials include clay minerals such as kaolinite , whereas more recent materials include aluminium oxide, more commonly known as alumina . Modern ceramic materials, which are classified as advanced ceramics, include silicon carbide and tungsten carbide . Both are valued for their abrasion resistance and are therefore used in applications such as
1144-423: A signal). The unit of time measured is the natural interval required for electricity to be converted into mechanical energy and back again. The piezoelectric effect is generally stronger in materials that also exhibit pyroelectricity , and all pyroelectric materials are also piezoelectric. These materials can be used to inter-convert between thermal, mechanical, or electrical energy; for instance, after synthesis in
1232-418: A stable electric dipole can be oriented or reversed by applying an electrostatic field. Pyroelectricity is also a necessary consequence of ferroelectricity. This can be used to store information in ferroelectric capacitors , elements of ferroelectric RAM . The most common such materials are lead zirconate titanate and barium titanate . Aside from the uses mentioned above, their strong piezoelectric response
1320-512: A waterproof barrier, and improve its durability. Below are the major types of glazing commonly used in pottery: 1. Glossy Glaze - Produces a shiny, reflective surface. - Highlights intricate patterns and textures. - Often used for decorative purposes. 2. Matte Glaze - Provides a smooth, non-reflective finish. - Suitable for modern and minimalist designs. - Ideal for functional wares like plates and mugs, as it minimizes glare. 3. Transparent Glaze - Can be glossy or matte. - Allows
1408-722: Is twinned with: Ceramic A ceramic is any of the various hard, brittle , heat-resistant , and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay , at a high temperature. Common examples are earthenware , porcelain , and brick . The earliest ceramics made by humans were fired clay bricks used for building house walls and other structures. Other pottery objects such as pots, vessels, vases and figurines were made from clay , either by itself or mixed with other materials like silica , hardened by sintering in fire. Later, ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through
1496-401: Is also important, the combination of heat and time is known as heatwork . Kilns can be monitored by pyrometers , thermocouples and pyrometric devices . The atmosphere within a kiln during firing can affect the appearance of the body and glaze. Key to this is the differing colours of the various oxides of iron, such as iron(III) oxide (also known as ferric oxide or Fe 2 O 3 ) which
1584-485: Is associated with brown-red colours, whilst iron(II) oxide (also known as ferrous oxide or FeO) is associated with much darker colours, including black. The oxygen concentration in the kiln influences the type, and relative proportions, of these iron oxides in fired the body and glaze: for example, where there is a lack of oxygen during firing the associated carbon monoxide (CO) will readily react with oxygen in Fe 2 O 3 in
1672-467: Is employed. Ice templating allows the creation of macroscopic pores in a unidirectional arrangement. The applications of this oxide strengthening technique are important for solid oxide fuel cells and water filtration devices. To process a sample through ice templating, an aqueous colloidal suspension is prepared to contain the dissolved ceramic powder evenly dispersed throughout the colloid, for example Yttria-stabilized zirconia (YSZ). The solution
1760-468: Is exploited in the design of high-frequency loudspeakers , transducers for sonar , and actuators for atomic force and scanning tunneling microscopes . Temperature increases can cause grain boundaries to suddenly become insulating in some semiconducting ceramic materials, mostly mixtures of heavy metal titanates . The critical transition temperature can be adjusted over a wide range by variations in chemistry. In such materials, current will pass through
1848-400: Is important part of archaeology for understanding the archaeological culture of the excavated site by studying the fabric of artifacts, such as their usage, source material composition, decorative pattern, color of patterns, etc. This helps to understand characteristics, sophistication , habits, technology, tools, trade, etc. of the people who made and used the pottery. Carbon dating reveals
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#17327905810441936-426: Is lit and the woman runs around the circumference of the mound touching the burning torch to the dried grass. Some mounds are still being constructed as others are already burning. Pottery may be decorated in many different ways. Some decoration can be done before or after the firing, and may be undertaken before or after glazing. Glaze is a glassy coating on pottery, and reasons to use it include decoration, ensuring
2024-425: Is made by heating materials, generally including kaolin , in a kiln to temperatures between 1,200 and 1,400 °C (2,200 and 2,600 °F). This is higher than used for the other types, and achieving these temperatures was a long struggle, as well as realizing what materials were needed. The toughness, strength and translucence of porcelain, relative to other types of pottery, arises mainly from vitrification and
2112-638: Is normally fired below 1200 °C. Because unglazed earthenware is porous, it has limited utility for the storage of liquids or as tableware. However, earthenware has had a continuous history from the Neolithic period to today. It can be made from a wide variety of clays, some of which fire to a buff, brown or black colour, with iron in the constituent minerals resulting in a reddish-brown. Reddish coloured varieties are called terracotta , especially when unglazed or used for sculpture. The development of ceramic glaze made impermeable pottery possible, improving
2200-481: Is not always the case; for example fritware uses no or little clay, so falls outside these groups. Historic pottery of all these types is often grouped as either "fine" wares, relatively expensive and well-made, and following the aesthetic taste of the culture concerned, or alternatively "coarse", "popular", "folk" or "village" wares, mostly undecorated, or simply so, and often less well-made. Cooking in pottery became less popular once metal pots became available, but
2288-480: Is not understood, but there are two major families of superconducting ceramics. Piezoelectricity , a link between electrical and mechanical response, is exhibited by a large number of ceramic materials, including the quartz used to measure time in watches and other electronics. Such devices use both properties of piezoelectrics, using electricity to produce a mechanical motion (powering the device) and then using this mechanical motion to produce electricity (generating
2376-430: Is placed within the context of linguistic and migratory patterns, it becomes an even more prevalent category of social artifact. As proposed by Olivier P. Gosselain, it is possible to understand ranges of cross-cultural interaction by looking closely at the chaîne opératoire of ceramic production. The methods used to produce pottery in early Sub-Saharan Africa are divisible into three categories: techniques visible to
2464-491: Is possible to distinguish between different cultural styles, the purpose of the ceramic, and the technological state of the people, among other conclusions. Besides, by looking at stylistic changes in ceramics over time, it is possible to separate (seriate) the ceramics into distinct diagnostic groups (assemblages). A comparison of ceramic artifacts with known dated assemblages allows for a chronological assignment of these pieces. The technical approach to ceramic analysis involves
2552-568: Is responsible for such diverse optical phenomena as night-vision and IR luminescence . Thus, there is an increasing need in the military sector for high-strength, robust materials which have the capability to transmit light ( electromagnetic waves ) in the visible (0.4 – 0.7 micrometers) and mid- infrared (1 – 5 micrometers) regions of the spectrum. These materials are needed for applications requiring transparent armor, including next-generation high-speed missiles and pods, as well as protection against improvised explosive devices (IED). In
2640-405: Is shaped by a variety of techniques, which include: Prior to firing, the water in an article needs to be removed. A number of different stages, or conditions of the article, can be identified: Firing produces permanent and irreversible chemical and physical changes in the body. It is only after firing that the article or material is pottery. In lower-fired pottery, the changes include sintering ,
2728-455: Is still used for dishes that benefit from the qualities of pottery cooking, typically slow cooking in an oven, such as biryani , cassoulet , daube , tagine , jollof rice , kedjenou , cazuela and types of baked beans . The earliest forms of pottery were made from clays that were fired at low temperatures, initially in pit-fires or in open bonfires . They were hand formed and undecorated. Earthenware can be fired as low as 600 °C, and
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2816-425: Is then cooled from the bottom to the top on a platform that allows for unidirectional cooling. This forces ice crystals to grow in compliance with the unidirectional cooling, and these ice crystals force the dissolved YSZ particles to the solidification front of the solid-liquid interphase boundary, resulting in pure ice crystals lined up unidirectionally alongside concentrated pockets of colloidal particles. The sample
2904-475: Is then heated and at the same the pressure is reduced enough to force the ice crystals to sublime and the YSZ pockets begin to anneal together to form macroscopically aligned ceramic microstructures. The sample is then further sintered to complete the evaporation of the residual water and the final consolidation of the ceramic microstructure. During ice-templating, a few variables can be controlled to influence
2992-472: Is typically somewhere between the minimum wavelength of visible light and the resolution limit of the naked eye. The microstructure includes most grains, secondary phases, grain boundaries, pores, micro-cracks, structural defects, and hardness micro indentions. Most bulk mechanical, optical, thermal, electrical, and magnetic properties are significantly affected by the observed microstructure. The fabrication method and process conditions are generally indicated by
3080-399: Is usually identified by microscopic examination of the tempered material. Clay identification is determined by a process of refiring the ceramic and assigning a color to it using Munsell Soil Color notation. By estimating both the clay and temper compositions and locating a region where both are known to occur, an assignment of the material source can be made. Based on the source assignment of
3168-473: Is virtually lossless. Optical waveguides are used as components in Integrated optical circuits (e.g. light-emitting diodes , LEDs) or as the transmission medium in local and long haul optical communication systems. Also of value to the emerging materials scientist is the sensitivity of materials to radiation in the thermal infrared (IR) portion of the electromagnetic spectrum . This heat-seeking ability
3256-400: The "clay matrix" – composed of grains of less than 0.02 mm grains which can be seen using the high-powered microscopes or a scanning electron microscope , and the "clay inclusions" – which are larger grains of clay and could be seen with the naked eye or a low-power binocular microscope. For geologists, fabric analysis means spatial arrangement of minerals in a rock. For Archaeologists,
3344-566: The "fabric analysis" of pottery entails the study of clay matrix and inclusions in the clay body as well as the firing temperature and conditions . Analysis is done to examine the following 3 in detail: The Six fabrics of Kalibangan is a good example of fabric analysis. Body , or clay body, is the material used to form pottery. Thus a potter might prepare, or order from a supplier, such an amount of earthenware body, stoneware body or porcelain body. The compositions of clay bodies varies considerably, and include both prepared and 'as dug';
3432-540: The Russian Far East (14,000 BC), Sub-Saharan Africa (9,400 BC), South America (9,000s–7,000s BC), and the Middle East (7,000s–6,000s BC). Pottery is made by forming a clay body into objects of a desired shape and heating them to high temperatures (600–1600 °C) in a bonfire , pit or kiln , which induces reactions that lead to permanent changes including increasing the strength and rigidity of
3520-886: The 1960s, scientists at General Electric (GE) discovered that under the right manufacturing conditions, some ceramics, especially aluminium oxide (alumina), could be made translucent . These translucent materials were transparent enough to be used for containing the electrical plasma generated in high- pressure sodium street lamps. During the past two decades, additional types of transparent ceramics have been developed for applications such as nose cones for heat-seeking missiles , windows for fighter aircraft , and scintillation counters for computed tomography scanners. Other ceramic materials, generally requiring greater purity in their make-up than those above, include forms of several chemical compounds, including: For convenience, ceramic products are usually divided into four main types; these are shown below with some examples: Frequently,
3608-532: The Hall-Petch equation, hardness , toughness , dielectric constant , and the optical properties exhibited by transparent materials . Ceramography is the art and science of preparation, examination, and evaluation of ceramic microstructures. Evaluation and characterization of ceramic microstructures are often implemented on similar spatial scales to that used commonly in the emerging field of nanotechnology: from nanometers to tens of micrometers (µm). This
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3696-503: The ability of the involved parties to communicate effectively, implying pre-existing norms of contact or a shared language between the two. Thus, the patterns of technical diffusion in pot-making that are visible via archaeological findings also reveal patterns in societal interaction. Chronologies based on pottery are often essential for dating non-literate cultures and are often of help in the dating of historic cultures as well. Trace-element analysis , mostly by neutron activation , allows
3784-452: The age. Sites with similar pottery characteristics have the same culture, those sites which have distinct cultural characteristics but with some overlap are indicative of cultural exchange such as trade or living in vicinity or continuity of habitation, etc. Examples are black and red ware , redware , Sothi-Siswal culture and Painted Grey Ware culture . The six fabrics of Kalibangan is a good example of use of fabric analysis in identifying
3872-427: The area of Sugwang-ri, Sindun-myeon, Saeum-dong, and a popular visitor attraction. They use traditional skills and produce porcelains in some 40 traditional firewood kilns. This pottery is recognized both at home and abroad for its quality. The Saeum-dong and Sindun-myeon areas also include a ceramics village with many ceramics stores. Potters have researched traditional methods and revived the manufacture of ceramics in
3960-494: The artifact, further investigations can be made into the site of manufacture. The physical properties of any ceramic substance are a direct result of its crystalline structure and chemical composition. Solid-state chemistry reveals the fundamental connection between microstructure and properties, such as localized density variations, grain size distribution, type of porosity, and second-phase content, which can all be correlated with ceramic properties such as mechanical strength σ by
4048-417: The branches and then grass is piled high to complete the mound. Although the mound contains the pots of many women, who are related through their husbands' extended families, each women is responsible for her own or her immediate family's pots within the mound. When a mound is completed and the ground around has been swept clean of residual combustible material, a senior potter lights the fire. A handful of grass
4136-513: The brightness and contrast of a digital image. Guided lightwave transmission via frequency selective waveguides involves the emerging field of fiber optics and the ability of certain glassy compositions as a transmission medium for a range of frequencies simultaneously ( multi-mode optical fiber ) with little or no interference between competing wavelengths or frequencies. This resonant mode of energy and data transmission via electromagnetic (light) wave propagation , though low powered,
4224-418: The ceramic family. Highly oriented crystalline ceramic materials are not amenable to a great range of processing. Methods for dealing with them tend to fall into one of two categories: either making the ceramic in the desired shape by reaction in situ or "forming" powders into the desired shape and then sintering to form a solid body. Ceramic forming techniques include shaping by hand (sometimes including
4312-471: The chemical erosion that occurs in other materials subjected to acidic or caustic environments. Ceramics generally can withstand very high temperatures, ranging from 1,000 °C to 1,600 °C (1,800 °F to 3,000 °F). The crystallinity of ceramic materials varies widely. Most often, fired ceramics are either vitrified or semi-vitrified, as is the case with earthenware, stoneware , and porcelain. Varying crystallinity and electron composition in
4400-627: The city will connect into the Seoul Metropolitan Subway via Yeoju Line 's Icheon Station. Icheon is divided into 2 towns ( eup ), 8 townships ( myeon ), and 4 neighbourhoods ( dong ). There are 230,000 people living, including about 220,000 Koreans and 11,000 foreigners. More than 1,200 companies employ about 40,000 people. Icheon has a humid continental climate ( Dwa in the Köppen climate classification ). The Icheon Ceramics Village features 300-plus ceramics-making firms in
4488-534: The class of ceramic matrix composite materials, in which ceramic fibers are embedded and with specific coatings are forming fiber bridges across any crack. This mechanism substantially increases the fracture toughness of such ceramics. Ceramic disc brakes are an example of using a ceramic matrix composite material manufactured with a specific process. Scientists are working on developing ceramic materials that can withstand significant deformation without breaking. A first such material that can deform in room temperature
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#17327905810444576-431: The cultural development of the societies that produced or acquired pottery. The study of pottery may also allow inferences to be drawn about a culture's daily life, religion, social relationships, attitudes towards neighbours, attitudes to their own world and even the way the culture understood the universe. It is valuable to look into pottery as an archaeological record of potential interaction between peoples. When pottery
4664-480: The duration of firing influences the final characteristics of the ceramic. Thus, the maximum temperature within a kiln is often held constant for a period of time to soak the wares to produce the maturity required in the body of the wares. Kilns may be heated by burning combustible materials, such as wood , coal and gas , or by electricity . The use of microwave energy has been investigated. When used as fuels, coal and wood can introduce smoke, soot and ash into
4752-457: The electrical properties that show grain boundary effects. One of the most widely used of these is the varistor. These are devices that exhibit the property that resistance drops sharply at a certain threshold voltage . Once the voltage across the device reaches the threshold, there is a breakdown of the electrical structure in the vicinity of the grain boundaries, which results in its electrical resistance dropping from several megohms down to
4840-460: The eye (decoration, firing and post-firing techniques), techniques related to the materials (selection or processing of clay, etc.), and techniques of molding or fashioning the clay. These three categories can be used to consider the implications of the reoccurrence of a particular sort of pottery in different areas. Generally, the techniques that are easily visible (the first category of those mentioned above) are thus readily imitated, and may indicate
4928-430: The following stages: Before being shaped, clay must be prepared. This may include kneading to ensure an even moisture content throughout the body. Air trapped within the clay body needs to be removed, or de-aired, and can be accomplished either by a machine called a vacuum pug or manually by wedging . Wedging can also help produce an even moisture content. Once a clay body has been kneaded and de-aired or wedged, it
5016-486: The foot) is left unglazed or, alternatively, special refractory " spurs " are used as supports. These are removed and discarded after the firing. Some specialised glazing techniques include: Types of Glazing in Pottery. Glazing in pottery is the process of applying a coating or layer of material to ceramics that, when fired, forms a vitreous or glass-like surface. Glazes enhance the aesthetic appeal of pottery, provide
5104-659: The formation of the mineral mullite within the body at these high temperatures. Although porcelain was first made in China , the Chinese traditionally do not recognise it as a distinct category, grouping it with stoneware as "high-fired" ware, opposed to "low-fired" earthenware. This confuses the issue of when it was first made. A degree of translucency and whiteness was achieved by the Tang dynasty (AD 618–906), and considerable quantities were being exported. The modern level of whiteness
5192-443: The former being by far the dominant type for studio and industry. The properties also vary considerably, and include plasticity and mechanical strength before firing; the firing temperature needed to mature them; properties after firing, such as permeability, mechanical strength and colour. There can be regional variations in the properties of raw materials used for pottery, and these can lead to wares that are unique in character to
5280-412: The fusing together of coarser particles in the body at their points of contact with each other. In the case of porcelain, where higher firing-temperatures are used, the physical, chemical and mineralogical properties of the constituents in the body are greatly altered. In all cases, the reason for firing is to permanently harden the wares, and the firing regime must be appropriate to the materials used. As
5368-460: The group as a whole. General properties such as high melting temperature, high hardness, poor conductivity, high moduli of elasticity , chemical resistance, and low ductility are the norm, with known exceptions to each of these rules ( piezoelectric ceramics , low glass transition temperature ceramics, superconductive ceramics ). Composites such as fiberglass and carbon fiber , while containing ceramic materials, are not considered to be part of
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#17327905810445456-632: The infrastructure from lightning strikes. They have rapid response, are low maintenance, and do not appreciably degrade from use, making them virtually ideal devices for this application. Semiconducting ceramics are also employed as gas sensors . When various gases are passed over a polycrystalline ceramic, its electrical resistance changes. With tuning to the possible gas mixtures, very inexpensive devices can be produced. Under some conditions, such as extremely low temperatures, some ceramics exhibit high-temperature superconductivity (in superconductivity, "high temperature" means above 30 K). The reason for this
5544-468: The ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators (researched in ceramic engineering ). With such a large range of possible options for the composition/structure of a ceramic (nearly all of the elements, nearly all types of bonding, and all levels of crystallinity), the breadth of the subject is vast, and identifiable attributes ( hardness , toughness , electrical conductivity ) are difficult to specify for
5632-417: The item is impermeable to liquids, and minimizing the adherence of pollutants. Glaze may be applied by spraying, dipping, trailing or brushing on an aqueous suspension of the unfired glaze. The colour of a glaze after it has been fired may be significantly different from before firing. To prevent glazed wares sticking to kiln furniture during firing, either a small part of the object being fired (for example,
5720-431: The kiln which can affect the appearance of unprotected wares. For this reason, wares fired in wood- or coal-fired kilns are often placed in the kiln in saggars , ceramic boxes, to protect them. Modern kilns fuelled by gas or electricity are cleaner and more easily controlled than older wood- or coal-fired kilns and often allow shorter firing times to be used. Niche techniques include: [...] pots are positioned on and amid
5808-586: The late Middle Ages, as European kilns were less efficient, and the right type of clay less common. It remained a speciality of Germany until the Renaissance. Stoneware is very tough and practical, and much of it has always been utilitarian, for the kitchen or storage rather than the table. But "fine" stoneware has been important in China , Japan and the West, and continues to be made. Many utilitarian types have also come to be appreciated as art. Porcelain
5896-486: The material near its critical temperature, the dielectric effect remains exceptionally strong even at much higher temperatures. Titanates with critical temperatures far below room temperature have become synonymous with "ceramic" in the context of ceramic capacitors for just this reason. Optically transparent materials focus on the response of a material to incoming light waves of a range of wavelengths. Frequency selective optical filters can be utilized to alter or enhance
5984-445: The material until joule heating brings it to the transition temperature, at which point the circuit will be broken and current flow will cease. Such ceramics are used as self-controlled heating elements in, for example, the rear-window defrost circuits of automobiles. At the transition temperature, the material's dielectric response becomes theoretically infinite. While a lack of temperature control would rule out any practical use of
6072-410: The mechanical performance of materials and components. It applies the physics of stress and strain , in particular the theories of elasticity and plasticity , to the microscopic crystallographic defects found in real materials in order to predict the macroscopic mechanical failure of bodies. Fractography is widely used with fracture mechanics to understand the causes of failures and also verify
6160-412: The microstructure. The root cause of many ceramic failures is evident in the cleaved and polished microstructure. Physical properties which constitute the field of materials science and engineering include the following: Mechanical properties are important in structural and building materials as well as textile fabrics. In modern materials science , fracture mechanics is an important tool in improving
6248-424: The object. Much pottery is purely utilitarian, but some can also be regarded as ceramic art . An article can be decorated before or after firing. Pottery is traditionally divided into three types: earthenware , stoneware and porcelain . All three may be glazed and unglazed. All may also be decorated by various techniques. In many examples the group a piece belongs to is immediately visually apparent, but this
6336-506: The popularity and practicality of pottery vessels. Decoration has evolved and developed through history. Stoneware is pottery that has been fired in a kiln at a relatively high temperature, from about 1,100 °C to 1,200 °C, and is stronger and non-porous to liquids. The Chinese, who developed stoneware very early on, classify this together with porcelain as high-fired wares. In contrast, stoneware could only be produced in Europe from
6424-718: The pore size and morphology of the microstructure. These important variables are the initial solids loading of the colloid, the cooling rate, the sintering temperature and duration, and the use of certain additives which can influence the microstructural morphology during the process. A good understanding of these parameters is essential to understanding the relationships between processing, microstructure, and mechanical properties of anisotropically porous materials. Some ceramics are semiconductors . Most of these are transition metal oxides that are II-VI semiconductors, such as zinc oxide . While there are prospects of mass-producing blue LEDs from zinc oxide, ceramicists are most interested in
6512-421: The raw materials and cause it to be reduced to FeO. An oxygen deficient condition, called a reducing atmosphere, is generated by preventing the complete combustion of the kiln fuel; this is achieved by deliberately restricting the supply of air or by supplying an excess of fuel. Firing pottery can be done using a variety of methods, with a kiln being the usual firing method. Both the maximum temperature and
6600-437: The raw materials of modern ceramics do not include clays. Those that do have been classified as: Ceramics can also be classified into three distinct material categories: Each one of these classes can be developed into unique material properties. Pottery Pottery is the process and the products of forming vessels and other objects with clay and other raw materials, which are fired at high temperatures to give them
6688-694: The root ceram- is the Mycenaean Greek ke-ra-me-we , workers of ceramic, written in Linear B syllabic script. The word ceramic can be used as an adjective to describe a material, product, or process, or it may be used as a noun, either singular or, more commonly, as the plural noun ceramics . Ceramic material is an inorganic, metallic oxide, nitride, or carbide material. Some elements, such as carbon or silicon , may be considered ceramics. Ceramic materials are brittle, hard, strong in compression, and weak in shearing and tension. They withstand
6776-745: The same material are called terracottas . Pottery is one of the oldest human inventions , originating before the Neolithic period , with ceramic objects such as the Gravettian culture Venus of Dolní Věstonice figurine discovered in the Czech Republic dating back to 29,000–25,000 BC. However, the earliest known pottery vessels were discovered in Jiangxi , China, which date back to 18,000 BC. Other early Neolithic and pre-Neolithic pottery artifacts have been found, in Jōmon Japan (10,500 BC),
6864-471: The sources of clay to be accurately identified and the thermoluminescence test can be used to provide an estimate of the date of last firing. Examining sherds from prehistory, scientists learned that during high-temperature firing, iron materials in clay record the state of the Earth's magnetic field at that moment. The "clay body" is also called the "paste" or the "fabric" , which consists of 2 things,
6952-412: The style of Goryeo celadon and Joseon white porcelain here. The village is the center of the effort to preserve these traditions. Icheon was designated as a UNESCO Creative City for Crafts and Folk Art, in in 2010. In 2018, the city was elected as the first designated city for Craft and Folk Art among South Korea's creative cities. It served as the designated city until September 2021. Icheon
7040-453: The theoretical failure predictions with real-life failures. Ceramic materials are usually ionic or covalent bonded materials. A material held together by either type of bond will tend to fracture before any plastic deformation takes place, which results in poor toughness in these materials. Additionally, because these materials tend to be porous, the pores and other microscopic imperfections act as stress concentrators , decreasing
7128-460: The toughness further, and reducing the tensile strength . These combine to give catastrophic failures , as opposed to the more ductile failure modes of metals. These materials do show plastic deformation . However, because of the rigid structure of crystalline material, there are very few available slip systems for dislocations to move, and so they deform very slowly. To overcome the brittle behavior, ceramic material development has introduced
7216-579: The underlying decoration or texture of the pottery to show through. - Often used over underglaze decorations. 4. Opaque Glaze - Completely covers the surface of the pottery, hiding any underlying texture or decoration. - Useful for creating uniform, bold colors. 5. Celadon Glaze - A translucent glaze, usually in shades of green or blue. - Originated in China and is popular in East Asian ceramics. - Accentuates carved or textured designs beneath
7304-565: The use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic, industrial, and building products, as well as a wide range of materials developed for use in advanced ceramic engineering, such as semiconductors . The word ceramic comes from the Ancient Greek word κεραμικός ( keramikós ), meaning "of or for pottery " (from κέραμος ( kéramos ) 'potter's clay, tile, pottery'). The earliest known mention of
7392-446: The wear plates of crushing equipment in mining operations. Advanced ceramics are also used in the medical, electrical, electronics, and armor industries. Human beings appear to have been making their own ceramics for at least 26,000 years, subjecting clay and silica to intense heat to fuse and form ceramic materials. The earliest found so far were in southern central Europe and were sculpted figures, not dishes. The earliest known pottery
7480-425: Was found in 2024. If a ceramic is subjected to substantial mechanical loading, it can undergo a process called ice-templating , which allows some control of the microstructure of the ceramic product and therefore some control of the mechanical properties. Ceramic engineers use this technique to tune the mechanical properties to their desired application. Specifically, the strength is increased when this technique
7568-503: Was made by mixing animal products with clay and firing it at up to 800 °C (1,500 °F). While pottery fragments have been found up to 19,000 years old, it was not until about 10,000 years later that regular pottery became common. An early people that spread across much of Europe is named after its use of pottery: the Corded Ware culture . These early Indo-European peoples decorated their pottery by wrapping it with rope while it
7656-520: Was not reached until much later, in the 14th century. Porcelain was also made in Korea and in Japan from the end of the 16th century, after suitable kaolin was located in those countries. It was not made effectively outside East Asia until the 18th century. The study of pottery can help to provide an insight into past cultures. Fabric analysis (see section below), used to analyse the fabric of pottery ,
7744-528: Was still wet. When the ceramics were fired, the rope burned off but left a decorative pattern of complex grooves on the surface. The invention of the wheel eventually led to the production of smoother, more even pottery using the wheel-forming (throwing) technique, like the pottery wheel . Early ceramics were porous, absorbing water easily. It became useful for more items with the discovery of glazing techniques, which involved coating pottery with silicon, bone ash, or other materials that could melt and reform into
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