Ceramics Solid

si3n4 ceramic bearing parts

ceramic solids composed of inorganic compounds, oxides of chemical elements. chemically inert, , capable of withstanding chemical erosion occurs in acidic or caustic environment. ceramics can withstand high temperatures ranging 1000 1600 °c (1800 3000 °f). exceptions include non-oxide inorganic materials, such nitrides, borides , carbides.

traditional ceramic raw materials include clay minerals such kaolinite, more recent materials include aluminium oxide (alumina). modern ceramic materials, classified advanced ceramics, include silicon carbide , tungsten carbide. both valued abrasion resistance, , hence find use in such applications wear plates of crushing equipment in mining operations.

most ceramic materials, such alumina , compounds, formed fine powders, yielding fine grained polycrystalline microstructure filled light scattering centers comparable wavelength of visible light. thus, opaque materials, opposed transparent materials. recent nanoscale (e.g. sol-gel) technology has, however, made possible production of polycrystalline transparent ceramics such transparent alumina , alumina compounds such applications high-power lasers. advanced ceramics used in medicine, electrical , electronics industries.

ceramic engineering science , technology of creating solid-state ceramic materials, parts , devices. done either action of heat, or, @ lower temperatures, using precipitation reactions chemical solutions. term includes purification of raw materials, study , production of chemical compounds concerned, formation components, , study of structure, composition , properties.

mechanically speaking, ceramic materials brittle, hard, strong in compression , weak in shearing , tension. brittle materials may exhibit significant tensile strength supporting static load. toughness indicates how energy material can absorb before mechanical failure, while fracture toughness (denoted kic ) describes ability of material inherent microstructural flaws resist fracture via crack growth , propagation. if material has large value of fracture toughness, basic principles of fracture mechanics suggest undergo ductile fracture. brittle fracture characteristic of ceramic , glass-ceramic materials typically exhibit low (and inconsistent) values of kic.

for example of applications of ceramics, extreme hardness of zirconia utilized in manufacture of knife blades, other industrial cutting tools. ceramics such alumina, boron carbide , silicon carbide have been used in bulletproof vests repel large-caliber rifle fire. silicon nitride parts used in ceramic ball bearings, high hardness makes them wear resistant. in general, ceramics chemically resistant , can used in wet environments steel bearings susceptible oxidation (or rust).

as example of ceramic applications, in 1980s, toyota researched production of adiabatic ceramic engine operating temperature of on 6000 °f (3300 °c). ceramic engines not require cooling system , hence allow major weight reduction , therefore greater fuel efficiency. in conventional metallic engine, of energy released fuel must dissipated waste heat in order prevent meltdown of metallic parts. work being done in developing ceramic parts gas turbine engines. turbine engines made ceramics operate more efficiently, giving aircraft greater range , payload set amount of fuel. however, such engines not in production because manufacturing of ceramic parts in sufficient precision , durability difficult , costly. processing methods result in wide distribution of microscopic flaws play detrimental role in sintering process, resulting in proliferation of cracks, , ultimate mechanical failure.