LaB6-ZrB2 composite powders with various contents of ZrB2 were synthesized by using the carbon thermo-reduction method, and the corresponding polycrystalline composites were fabricated by using the hot-pressing sintering method. The results showed that the hardness and bending strength of LaB6-ZrB2 polycrystals were enhanced with increasing ZrB2 content, while the fracture toughness first increased and then decreased; reaching the optimum value when the mass fraction of ZrB2 was 21%.

Influence of ZrB2 Content on Properties of LaB6-ZrB2 Composites. Gao, R., Yu, H., Han, J., Min, G., Paderno, Y.B.: Journal of the Chinese Ceramic Society, 2004, 32[4], 507-23