Ceramics

Ceramics are inorganic, non-metallic materials typically formed by shaping and firing at high temperatures. They consist mainly of compounds of elements such as silicon, aluminum, oxygen, and nitrogen. Traditional ceramics include pottery, bricks, tiles, and porcelain, while advanced ceramics are engineered for high performance in demanding environments.

Traditional ceramics are made from natural raw materials such as clays (kaolin, ball clay), feldspars, quartz, and lime. After forming, items are dried and fired to vitrify the body and develop strength. Glazes may be applied to create a glassy surface.

Advanced ceramics include alumina, silicon carbide, silicon nitride, zirconia, and boron nitride. They offer high hardness, high temperature stability, corrosion resistance, and low wear. They are manufactured through powder processing, pressing, sintering, and sometimes chemical vapor deposition or hot isostatic pressing. They can be used in electronics, medical implants, cutting tools, automotive components, aerospace, and other applications requiring heat resistance and durability.

Properties of ceramics typically include brittleness, high compressive strength, high melting points, and low to moderate thermal conductivity. They often exhibit chemical inertness and good wear resistance. Electrical properties vary; many traditional ceramics act as insulators, while some advanced ceramics are semiconductive or exhibit dielectric behavior. Thermal expansion and compatibility with other materials are important design considerations.

History and development trace ceramics from ancient pottery and bricks to porcelain and refractories, extending into modern times with ceramic matrix composites, bioactive ceramics, and a range of engineering applications.