Reaction-Bonded Three-Layer Alumina-Based Composites with Improved Damage Resistance

Three-layer alumina-based composites with Al 2 O 3 -containing mullite as an outer layer and ZrO 2 -containing alumina as an inner layer were fabricated by die-pressing and reaction-bonding. The strength of samples with Vickers indents made at loads up to 300 N was investigated. When compared to monolithic ceramics, three-layer composites exhibit excellent damage resistance due to compressive stresses in the outer layer. Hot isostatically pressed samples show a four-point bend strength of 800 MPa after indentation at 300 N.