Influence of the content of ZrxAlyCz on properties of ZrB2-ZrxAlyCz Composite Ceramics Fabricated by Spark Plasma Sintering

Abstract ZrB2/ZrxAlyCz composite ceramics with different volume contents of ZrxAlyCz were fabricated by the spark plasma sintering. The sintering behavior, microstructure, mechanical properties and oxidation resistance were studied. The results indicated that sinterability of the composites was remarkably improved by addition of ZrxAlyCz compared to the single-phase ZrB2 ceramic. As the content of ZrxAlyCz increased, both the Vickers hardness and Young’s modulus of the composites first increased and then decreased. The fracture toughness of the ZrB2-40vol% ZrxAlyCz composite was 3.56 MPa·m1/2, which increased by approximately 70% compared to the monolithic ZrB2 ceramic. As increasing the content of ZrxAlyCz, the oxidation resistance of composite ceramics was obviously enhanced. The oxidation-resulted increase in weight of composite ceramic with 20vol% ZrxAlyCz was the best performance in oxidation resistance at 1500 °C. The high-temperature oxidation resulted in dense and stable Al-B-O glass due to adding ZrxAlyCz into the composite ceramics, those resulting products effectively blocked the oxygen atoms entering into the ceramic matrix.