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55-592: The Medalta Potteries was a Canadian ceramics manufacturing company in Medicine Hat , Alberta , that operated from 1916 to 1954. It was the first manufacturer in Western Canada to ship its products east of Ontario . The rich natural resources in the area surrounding Medicine Hat provided impetus for the development of industry. Among them was natural gas , used for heating, lighting, and to generate electricity for powering industrial operations. Most Canadians at

110-505: 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

165-489: A financial advantage over Medalta, as its customs dues were 15% lower. In 1924, the company was reorganized and renamed to "Medalta Potteries", at the time producing 75% of Canada's stoneware , including that for the entire western Canada market. The company discontinued its manufacture of red clay flower pots at this time, instead focusing on more decorative flower pots with a cream-coloured glazing that had become popular amongst its customers. A buyer for Eaton's wrote to

220-514: 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

275-422: 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

330-669: 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

385-492: 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

440-434: 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

495-423: 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

550-543: A site near Willows , and the stoneware clays were obtained from Eastend and Ravenscrag . The company constantly had a clay surplus, which it sold to brick manufacturers and Vancouver schools. The clay was processed in the factory (now known as the Old Factory ), and the ceramics produced in the Turning Room. Among the products manufactured were beanpots , butter churns , crocks , mixing bowls, and water coolers. During

605-418: 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

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660-467: 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

715-468: 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

770-480: 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

825-491: 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

880-568: 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

935-425: 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

990-472: 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

1045-472: 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

1100-399: 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

1155-467: 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

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1210-467: The Great Depression of the 1930s, the company's officers permitted travellers to use the cooling kilns as a temporary accommodation as they crossed the country in search of work. The kilns could house up to 40 people overnight; they were required to vacate the premises before the start of the next workday. The manufacturing complex was restored, and is now a working museum. In a building adjacent to

1265-886: 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,

1320-526: 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

1375-697: The Shaw International Centre for Contemporary Ceramics in which the gallery is housed. 50°01′54″N 110°38′59″W  /  50.03167°N 110.64972°W  / 50.03167; -110.64972 Ceramic 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

1430-494: 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

1485-523: The beanpot minimizes evaporation and heat loss, while its deep, wide, thick-walled body facilitates long, slow cooking times. Beanpots are commonly associated with New England , in particular Boston, Massachusetts . This association is evident in the nickname Beantown , and the use of the name beanpot for Boston events such as the Beanpot ice hockey tournament. Beanpots resemble the Indian handi and

1540-513: 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,

1595-418: 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

1650-405: The ceramics at Medalta Potteries was imported from Saskatchewan, as the local clay was unsuitable for such use. The clay provisioned by Medalta included three varieties. From Chocolate Drop Hill near Eastend the company received shipments of a "chocolate clay", a dark clay that "burned a lighter colour than stoneware clay". A clay known as "Saskatchewan Ball Clay" that burned white was obtained from

1705-471: 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

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1760-534: 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

1815-615: The company, requesting that it "make a real flower pot". In 1928, after purchasing a used press from Montana and quarrying red clay from the surrounding land, it began manufacturing red clay pots again. Despite its success, the company made little profit and was constantly searching for used equipment it could obtain inexpensively to expand its business. With a workforce of 82 employees earning an average of $ 3.25 per hour, Medalta's labour costs were significantly higher than those of manufacturers of imported ceramics from Austria, Czechoslovakia, England, France, Germany, and Japan. It also relied on

1870-457: 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

1925-460: 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

1980-632: 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

2035-468: 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

2090-486: 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

2145-445: 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

2200-410: 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

2255-412: 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

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2310-718: 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

2365-637: The railways to ship its source material, which it obtained from numerous sources. From Ohio it obtained stilts , wire cloth, and cones . Chicago was the source of pickle jar wire and "red seal zinc white", and New York was the source for various chemicals, including barium , iron oxide , manganese , nickel , oxides of chromium , and "black under glaze". From England it obtained sponges , from New Brunswick came plaster of Paris , from Toronto came ground feldspar , from Winnipeg came gilders whiting (finely crushed chalk ), and from Deloro, Ontario came black cobalt oxide . The clay used for manufacturing

2420-497: 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. Beanpot A beanpot is a deep, wide-bellied, short-necked vessel used to cook bean -based dishes. Beanpots are typically made of ceramic , though some are made of other materials, such as cast iron . The relatively narrow mouth of

2475-683: 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

2530-671: The site replicas of Medalta pottery are manufactured, to be sold in the museum gift shop . Several galleries are located in the complex. These include: the Collector's Gallery, located near the kilns and exhibiting the Tony Schlachter Collection; the Yuill Family Gallery of contemporary works, for travelling exhibits and works by resident artists; and the Les Manning Gallery, named for the ceramic artist who conceived

2585-453: 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

2640-676: The time bought ceramic products from large, established manufacturers based in the United States, particularly Red Wing Stoneware of Red Wing, Minnesota , in western Canada, and Ohio potteries in eastern Canada. Three partners established Medalta Stoneware in 1916, starting with 12 employees, to prove that Canadian-made ceramics could compete with those from the United States, and that it was "equal in quality to any made in America". The company's products gradually displaced American-made ceramics at western Canadian retailers. The plant became famous, and

2695-460: 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

2750-558: 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

2805-446: 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

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2860-528: Was an attraction for dignitaries, being visited by Lord Byng , the Duke of Devonshire , and the Prince of Wales by 1920. In 1921, it became the first western Canadian company to ship goods other than cereal grains east of Manitoba. Its incursion into the eastern Canadian market posed the first serious competition for Robinson Clay Products of Ohio in that market, which it met by decreasing its prices by 25%. Robinson Clay had

2915-425: 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

2970-497: 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

3025-528: 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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