Influence of ZrO2 addition on the structure, thermal stability, and dielectric properties of ZnTiO3 ceramics

The zinc titanates doped with zirconium were synthesized by conventional solid-state reaction using metal oxides. X-ray diffractometry and differential scanning calorimetry analysis results indicated that the stable region of the hexagonal Zn(ZrxTi1-x)O3 phase extended to a high temperature (above 945 C). The c/a value decreased as the Zr concentrations increased, which may be caused by the Zr4? addition resulting in a shorter distance between the center ion and its nearest neighbors of the octahedron, and the bonding force between the B-site ion and oxygen ion of ABO3 perovskite-like structure becoming stronger. The dielectric properties exhibited a significant dependence on the sintering temperatures and the amount of ZrO2 addition. The dielectric constant decreased and Curie temperature (Tc) increased slightly with the increasing amounts of Zr ions. This is caused by the second phase of ZnZrO3 which was deposited at the grain boundaries and inhibited the grain growth. Furthermore, diffuse phase transition with a maximum permittivity at a transition temperature that is close to room temperature in Zn(ZrxTi1-x)O3 was observed