Introduction to Ceramics
Ceramics are non-metallic, inorganic solid materials made by taking mixtures of clay, earthen elements, powders, and water. This mixture is then molded into various shapes and forms and heated to high temperatures to make them hard. Ceramics are mostly brittle, rigid, and resistant to corrosion. Quality of the ceramic material depends upon the types of atom and atomic bonds present and how the atoms are packed together in the material. Ceramic materials can be crystalline, glassy or both crystalline and glassy. These are chemically non-reactive materials. Ceramics are produced for a range of uses, such as flooring and tiles, foodware, whiteware, arts and aesthetics, and other industrial uses.
Types of Ceramics
Traditional Ceramics: Earthenware, porcelain and stoneware are examples of traditional, clay-based ceramics items. The nature of the end product produced depends on the composition of the clays used, type of additives and firing temperatures used for hardening. Porcelain is made by grounding small amounts of glass, granite and feldspar minerals with fine white kaolin clay. Finally, water is added to the resulting fine white powder and the resultant mixture is kneaded and worked into various shapes.
Advanced ceramics: These are new materials and not clay based, rather they are based on oxides or non-oxides or combinations of the two. Advanced ceramics are made up of typical oxides alumina (Al2O3) and zirconia (ZrO2) and/or non-oxides such as carbides, borides, nitrides and silicides, for example, boron carbide (B4C), silicon carbide (SiC) and molybdenum disilicide (MoSi2). For production, very fine constituent material powders are thoroughly blended, shaped and subjected to high temperatures (1,600–1,800°C) in oxygen free conditions. At high temperatures, the tiny grains of the individual ceramic components fuse together forming a hard, tough, durable and corrosion-resistant product. This process is called sintering.
Applications of Advanced Ceramics
Ceramics are used in a wide range of industries including aerospace, electronics, metals production and processing, aerospace, electronics, automotive and personnel protection. Ceramic materials find use in electronic components as they may be semiconducting, superconducting, ferroelectric, or an insulator, depending on their composition. Other applications include making objects like spark plugs, fiber optics, artificial joints, space shuttle tiles, cooktops, race car brakes, bioceramics, micropositioners, chemical sensors, self lubricating bearings, body armor, and skis.
