Highly efficient preparation of 0.2ZrO2/ZrSiO4 bulk ceramics with high density and hardness by molten-salt method and hot-pressing sintering

Using conventional solid state sintering method to synthesize ZrSiO 4 ceramics may result in high temperature and time consumption. Herein, a novel preparation route combining the advantages of molten-salt method and hot-pressing sintering (MH) was developed and used to efficiently prepare 0.2ZrO 2 /ZrSiO 4 ceramics (Z/Z). The phase structure, micromorphology, compactness and hardness of the obtained ceramics affected by the salt to oxide ratio, sintering temperature and holding time were investigated and discussed. It was found that the obtained Z/Z ceramics with high density (95.44 % of theoretical density) and high hardness (12.77 GPa) were prepared by the MH at low temperature and short holding time. The discussion of the results revealed that the optimum ratio of salt to oxide was 10: 1, molten-salt sintering conditions were 1300 °C and 6 h, hot-pressing sintering conditions were 64 MPa, 1200 °C and 0.5 h. The results demonstrated that the novel preparation route could be extended to prepare other high-performance ceramics.