Composites based on ZrO2 stabilized with CaO and CaAl4O7 were sintered via two different techniques: Conventional Sintering route and Spark Plasma Sintering (SPS) between 1200 and 1400 oC. The effectiveness of sintering technique applied on the stabilization degree of ZrO2 (conversion to c-ZrO2, Ca0.15Zr0.85O1.85), microstructure, densification and Vickers hardness of the composites was evaluated. The SPS represented a remarkable advance in the c-ZrO2 formation and also resulted in a high densification of the composites (inclusive at 1200 oC) which attained relative densities higher than 0.95. The advantage of SPS technique was mainly evidenced by the high densification of composites with high CaAl4O7 content. Therefore, the composites sintered by SPS exhibited higher hardness (10 GPa) compared to that of composites produced via conventional sintering (6 GPa).

Keywords: ZrO2 composites, Ca-stabilized zirconia, Spark plasma sintering, Calcium dialuminate.