Kiln furniture are devices and implements inside furnaces used during the heating of manufactured individual pieces, such as pottery or other ceramic or metal components. [1] Kiln furniture is made of refractory materials, i.e., materials that withstand high temperatures without deformation. [2] Kiln furniture can account for up to 80% of the mass of a kiln charge. [3]
Commonly used materials are cordierite (up to 1275 °C), mullite (up to 1750 °C), silicon carbide (up to 1500 °C), alumina (up to 1750 °C), zirconia (up to 1650 °C). The choice depends on cost, weight, and physical properties. [2]
Functions of kiln furniture include carrying the kiln/furnace load and protecting the load from various kind of damage: open file, smoke, debris, from deforming or sticking the components to each other. In addition to various carriers and plates, capsules with heating material may be used. [1]
Kiln furniture influences the heat distribution in the furnace and the interaction of the load with the atmosphere in the furnace. Since the furniture is being heated along with the load, this increases energy consumption hence the operating costs increase. An additional increase of costs comes from wear of the furniture due to thermomechanical and chemical stresses. To decrease heat capacity porous materials or thinner furniture components may be used. However this calls for a trade-off with load-bearing capacity and stress resistance. [1]
A saggar (also misspelled as sagger or segger) is a ceramic boxlike container used in the firing of pottery to enclose or protect ware being fired inside a kiln. [4] [5] [6] Saggars have been used to protect, or safeguard, ware from open flame, smoke, gases and kiln debris. [7] Traditionally, saggars were made primarily from fireclay. [8] [9] Modern saggars are made of alumina ceramic, cordierite ceramic, mullite ceramic silicon carbide [10] [11] and in special cases from zirconia. [12]
A pernette or stilt is a prop to support pottery in a kiln so that pottery does not touch each other or kiln's floor. [13] In archaeology, they may be upside-down fired clay tripods, leaving characteristic marks at the bottoms of the pottery/porcelain. [14] [15] They expose the bottom of the fired piece to the full heat. [16]
Other types of furniture and furniture systems include kiln cars, kiln shelves, batts, tiles, and plates; tubes and beams; props and fittings, profile setters, rollers, stools; T-cranks, Y-cranks, pin cranks. [17] The design of kiln furniture system depends on the wares manufactured: structural clay products, dinnerware, tiles, electronics ceramics, sanitaryware, electrical porcelain, etc. [2]
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.
A kiln is a thermally insulated chamber, a type of oven, that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes. Kilns have been used for millennia to turn objects made from clay into pottery, tiles and bricks. Various industries use rotary kilns for pyroprocessing and to transform many other materials.
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 a hard and durable form. The place where such wares are made by a potter is also called a pottery. 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, sanitaryware, 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 vessels only, and sculpted figurines of the same material are called terracottas.
Fire clay is a range of refractory clays used in the manufacture of ceramics, especially fire brick. The United States Environmental Protection Agency defines fire clay very generally as a "mineral aggregate composed of hydrous silicates of aluminium (Al2O3·2SiO2·2H2O) with or without free silica."
In materials science, a refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Refractories are polycrystalline, polyphase, inorganic, non-metallic, porous, and heterogeneous. They are typically composed of oxides or carbides, nitrides etc. of the following materials: silicon, aluminium, magnesium, calcium, boron, chromium and zirconium.
A fire brick, firebrick, or refractory is a block of ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. A refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency. Usually dense firebricks are used in applications with extreme mechanical, chemical, or thermal stresses, such as the inside of a wood-fired kiln or a furnace, which is subject to abrasion from wood, fluxing from ash or slag, and high temperatures. In other, less harsh situations, such as in an electric- or natural gas-fired kiln, more porous bricks, commonly known as "kiln bricks", are a better choice. They are weaker, but they are much lighter and easier to form and insulate far better than dense bricks. In any case, firebricks should not spall, and their strength should hold up well during rapid temperature changes.
Dental porcelain is a dental material used by dental technicians to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers. Evidence suggests they are an effective material as they are biocompatible, aesthetic, insoluble and have a hardness of 7 on the Mohs scale. For certain dental prostheses, such as three-unit molars porcelain fused to metal or in complete porcelain group, zirconia-based restorations are recommended.
A saggar is a type of kiln furniture. It is a ceramic boxlike container used in the firing of pottery to enclose or protect ware being fired inside a kiln. The name may be a contraction of the word safeguard.
Ceramic engineering is the science and technology of creating objects from inorganic, non-metallic materials. This is done either by the action of heat, or at lower temperatures using precipitation reactions from high-purity chemical solutions. The term includes the purification of raw materials, the study and production of the chemical compounds concerned, their formation into components and the study of their structure, composition and properties.
Ceramic glaze, or simply glaze, is a glassy coating on ceramics. It is used for decoration, to ensure the item is impermeable to liquids and to minimise the adherence of pollutants.
Ceramic membranes are a type of artificial membranes made from inorganic materials. They are used in membrane operations for liquid filtration.
This is a list of pottery and ceramic terms.
Ceramography is the art and science of preparation, examination and evaluation of ceramic microstructures. Ceramography can be thought of as the metallography of ceramics. The microstructure is the structure level of approximately 0.1 to 100 µm, 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 and hardness microindentations. Most bulk mechanical, optical, thermal, electrical and magnetic properties are significantly affected by the microstructure. The fabrication method and process conditions are generally indicated by the microstructure. The root cause of many ceramic failures is evident in the microstructure. Ceramography is part of the broader field of materialography, which includes all the microscopic techniques of material analysis, such as metallography, petrography and plastography. Ceramography is usually reserved for high-performance ceramics for industrial applications, such as 85–99.9% alumina (Al2O3) in Fig. 1, zirconia (ZrO2), silicon carbide (SiC), silicon nitride (Si3N4), and ceramic-matrix composites. It is seldom used on whiteware ceramics such as sanitaryware, wall tiles and dishware.
The room-temperature form of quartz, α-quartz, undergoes a reversible change in crystal structure at 573 °C to form β-quartz. This phenomenon is called an inversion, and for the α to β quartz inversion is accompanied by a linear expansion of 0.45%. This inversion can lead to cracking of ceramic ware if cooling occurs too quickly through the inversion temperature. This is called dunting, and the resultant faults as dunts. To avoid such thermal shock faults, cooling rates not exceeding 50 °C/hour have been recommended.
CoorsTek, Inc. is a privately owned manufacturer of technical ceramics for aerospace, automotive, chemical, electronics, medical, metallurgical, oil and gas, semiconductor and many other industries. CoorsTek headquarters and primary factories are located in Golden, Colorado, US. The company is wholly owned by Keystone Holdings LLC, a trust of the Coors family. John K. Coors, a great-grandson of founder and brewing magnate Adolph Coors, Sr., and the fifth and youngest son of longtime chairman and president Joseph Coors, retired as president and chairman in January 2020 after 22 years at the helm.
In materials science, ceramic matrix composites (CMCs) are a subgroup of composite materials and a subgroup of ceramics. They consist of ceramic fibers embedded in a ceramic matrix. The fibers and the matrix both can consist of any ceramic material, whereby carbon and carbon fibers can also be regarded as a ceramic material.
Carborundum Universal Ltd (CUMI), a part of Murugappa Group, is one of the largest and oldest conglomerates in India. CUMI is the leading manufacturer and developer of abrasives, ceramics, refractories, aluminium oxide grains, machine tools, polymers, adhesives and electro minerals in India.
Dick Lehman is an American ceramics artist based in Indiana. Dozens of articles and photos featuring his techniques and insights have appeared in periodicals and books on ceramic art since 1985, including 34 articles in U.S.-published Ceramics Monthly, the largest circulating magazine in the field, plus articles in 11 other international periodicals.
The mantou kiln or horseshoe-shaped kiln was the most common type of pottery kiln in north China, in historical periods when the dragon kiln dominated south China; both seem to have emerged in the Warring States period of approximately 475 to 221 BC. It is named after the Chinese mantou bun or roll, whose shape it resembles; the ground plan resembles a horseshoe. The kilns are roughly round, with a low dome covering the central firing area, and are generally only 2 to 3 metres across inside. However it is capable of reaching very high temperatures, up to about 1370°C. There is a door or bricked-up opening at the front for loading and unloading, and one or two short chimneys at the rear.
Stilts are small supports used when firing glazed ceramics to stop the melting glaze from fusing them to each other or the kiln. Stilts are a form of kiln furniture. Their presence in archaeological sites, where they may be known as pernette, along with other kiln furniture such as saggars and kiln bars can be used to support a case for local production. Some potters avoid the need for stilts by not glazing the bottom of their products. This is known as dry footing.
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