Microstructure and properties of SrTiO3/ZrO2 ceramic composites prepared through pressureless sintering

Zirconia (ZrO2) ceramics have excellent mechanical properties; however, their electrical properties are poor, which significantly limits their applications in electronic communication devices. To broaden the application field of ZrO2 ceramics, SrTiO3 with excellent dielectric properties was added to ZrO2 in this study, and SrTiO3/ZrO2 ceramic composites were prepared through pressureless sintering. The effects of SrTiO3 contents on the microstructure and properties of SrTiO3/ZrO2 ceramics were studied. The results indicated that the sintered sample contained t-ZrO2 and SrTiO3 phases. The SrTiO3 phase was uniformly distributed in the ZrO2 matrix. Within certain temperature and frequency ranges, the SrTiO3/ZrO2 ceramic composites exhibited stable relative dielectric constant and dielectric loss. When the SrTiO3 content was 35 wt%, the SrTiO3/ZrO2 ceramic composites exhibited the best comprehensive properties, with the relative density, open porosity, fracture toughness, bending strength, Vickers hardness, relative dielectric constant, and dielectric loss being 98.7%, 0.21%, 7.27 MPa m1/2, 404 MPa, 11.8 GPa, 105, and 0.003, respectively.