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Electrical insulators and dielectric materials are ceramics with intrinsically low electrical conductivity. Internal porosity lowers bulk electrical conductivity. Insulators for DC or low frequency AC devices must have a high resistivity, good thermal resistivity, and low dilation coefficient in order to have sufficient resistance to thermal shock. The porosity must be very low. The surface vitrification must be perfect to avoid water absorption and improve mechanical resistance. The most commonly used materials are porcelains, mainly ternary compounds (Al2O3-SiO2-MgO). Such insulators are used especially as supports for electric oven resistors or heating elements. Ceramics used for high frequency insulator applications require a low dielectric constant and a small loss tangent. The careful choice of raw materials saves the surface from having to be vitrified. A vitrified surface would increase the value of the dissipation factor. For very high frequencies (VHF), high-purity dense alumina, fired at temperatures above 1600°C, is generally used. For powerful tubes, large alumina insulators must be assembled on metallic electrodes. This application is used for television or satellite transmitter tubes, for microwave generators used for heating, and for powerful lasers. Products & Services
Industrial ceramic materials are non-metallic, inorganic compounds that include oxides, carbides, or nitrides. They have high melting points, low wear resistance, and a wide range of electrical properties.
Ceramic tube and ceramic rod products are suitable for use in applications requiring high temperature strength, erosion resistance, electrical or thermal insulation, and other specialized characteristics.
Ceramic balls are rolling, spherical elements that are used in check and ball valves, bearings, and other mechanical devices that provide rotary or linear motion. They can provide higher stiffness, lower thermal expansion, lighter weight, increased corrosion resistance, and higher electrical resistance than comparable steel products.
Specialty ceramics include nitrides, borides, carbon or graphite and silicides as well as other specialized non-metallic compounds.
Dielectric ceramics and substrates are electrical insulators with dielectric strength, dielectric constant and loss tangent values tailored for specific device applications.
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Topics of Interest
Zirconia or zirconium oxide (ZrO2) is an extremely refractory compound of zirconium and oxygen. Zirconia may have additions of calcia, magnesia or baria to stabilize the structure into a cubic...
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All materials can be characterized as either electrical conductors or as electrical insulators. A conductor is a material through which an electrical current can pass and an insulator is a material...
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Alumina or aluminum oxide (Al2O3) is a compound that consists of aluminum and oxygen. It is typically used in the alpha alumina structural form. In its pure form, alumina is a white ceramic material...
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Steatite or steatite porcelains are based on hydrated magnesium silicate (3MgO-4SiO2-4H2O) and are similar in composition to naturally occurring soapstone or mineral talc. Steatite ceramics may also...
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Technical Articles
Dielectric Strength for Insulators
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Dielectric Dissipation Factor
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Dielectric Breakdown Strength
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Dielectric Current
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Complex Sheer Rate
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Cone Penetration
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Compression Set
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Magnetic Permeability
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Modulus of Resilience
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Electrical Barrier Material - Voltoid® D-100 FR
- Electrical Distribution and Protection Equipment
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