Apple Inc.
Ceramic having a residual compressive stress for use in electronic devices

Abstract:

A toughened ceramic component having a residual compressive stress and methods of forming the toughened ceramic component is disclosed. The ceramic component may include an internal portion having a first coefficient of thermal expansion (CTE) and an external portion substantially surrounding the internal portion and forming an exterior surface of the ceramic component. The external portion may have a second CTE that is less than the first CTE. Additionally, the external portion may be in compressive stress.