Alumina ceramic is characterised by its high mechanical strength, hardness, wear resistance, high insulation resistance, low dielectric losses, vacuum-tightness and chemical endurance. Alumina is used for highly stressed parts for applications in mechanical, electrical and chemical engineering, electronics, vacuum technologies, food industry and in the manufacture of grinding elements require a variety of grades. Major industrial applications: specials, rings, bushings, wire drawing dies, tubes, gauges, brazed joint metal-ceramic parts.
Brazing is a metal-joining process whereby a filler metal is heated above and distributed between two or more close-fitting parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected by a suitable atmosphere, usually a flux. It then flows over the base metal (known as wetting) and is then cooled to join the workpieces together. It is similar to soldering, except the temperatures used to melt the filler metal are above 450 °C (842 °F).
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous (e.g., a glass). Because most common ceramics are crystalline, the definition of ceramic is often restricted to inorganic crystalline materials, as opposed to the noncrystalline glasses.
Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys.
Cordierite is highly resistant to thermal shock, has a low thermal expansion, provides excellent insulation properties in high relative humidity conditions and is highly resistant to aggressive substances. Major industrial applications: power switch components, regulating rheostat components, catalyst substrates.
A green body refers to a ceramic or porcelain compound, usually clay or powder, produced by slipcasting before it has been fired or sintered, respectively. -Sintering and Solid state chemistry.
Invar, also known generically as FeNi36 (64FeNi in the US), is a nickel steel alloy notable for its uniquely low coefficient of thermal expansion (CTE or α). The name, Invar, comes from the word invariable, referring to its lack of expansion or contraction with temperature changes.
FeNiCo alloys—named Kovar or Dilver P—that have the same expansion behaviour as borosilicate glass, and because of that are used for optical parts in a wide range of temperatures and applications, such as satellites.
Metallized ceramic is a product that generally consists of a ceramic insulator and a metal conductive coating. The coating can be applied automatically or by hand. The item is then dried and fired at high temperatures in special furnaces. When the coating is applied it offers very little conductivity but after firing the coating is quite conductive.
Is nickel plating necessary?
If the metallized ceramic component is to be brazed into a package or to another component, often nickel plating is necessary to guarantee good adhesion depending on the chosen braze material. Nickel also helps protect the molybdenum contained in many thick film metallization formulation. Electrolytic nickel is commonly employed. Another popular choice for post-metallization plating is electroless nickel. Nickel plating is not always necessary but it is very common and helpful.
Steatite with its excellent mechanical and electrical properties such as strength and electric insulation resistance is suitable for applications in electrical engineering and manufacture of metallised ceramics. Major industrial applications: specials, tubes, plates, bushings, coils, supports, ceramic capillary tubes.