From their website:
Headquartered in Costa Mesa, California, Ceradyne Inc. is a fully integrated developer and manufacturer of advanced technical ceramic products and components for defense, industrial, nuclear power, oil and gas, solar energy, electronic, automotive/transportation and medical markets.
Founded in 1967, Ceradyne has diversified its product lines to capture opportunities created by the growing demand for better materials performance. In late 2004, the company added new product lines and new markets—and one of the world’s leading suppliers of starting powders for manufacturing advanced ceramics products—by acquiring ESK Ceramics of Kempten, Germany.
The unique characteristics of advanced technical ceramics—hardness, light weight, ability to withstand extremely high temperatures, resistance to wear and corrosion, low friction, and special electrical properties—offer significant advantages over traditional materials such as metals and plastics. As a result, Ceradyne continues to develop new uses for ceramics and offers a diversified line of high performance ceramic products for a wide range of markets.