The Enhanced Thermal Stability of (Mg 0.95 Ni 0.05 ) 2 TiO 4 Dielectric Ceramics Modified by a Multi-Phase Method.

The thermal stability of (Mg 0.95 Ni 0.05 ) 2 TiO 4 dielectric ceramics has been improved by mixing with CaTiO 3 phases owing to higher positive temperature coefficients. The pure (Mg 0.95 Ni 0.05 ) 2 TiO 4 and the mixture phase systems of CaTiO 3 -modified (Mg 0.95 Ni 0.05 ) 2 TiO 4 were verified by XRD diffraction patterns to ensure the crystallite of different phases. The microstructures of the CaTiO 3 -modified (Mg 0.95 Ni 0.05 ) 2 TiO 4 were observed by SEM and EDS to investigate the relation between element ratios and grains. As a result, it can be seen that the thermal stability of the CaTiO 3 -modified (Mg 0.95 Ni 0.05 ) 2 TiO 4 can be effectively enhanced, compared with the pure (Mg 0.95 Ni 0.05 ) 2 TiO 4 . Moreover, the radio frequency dielectric performances of CaTiO 3 -modified (Mg 0.95 Ni 0.05 ) 2 TiO 4 dielectric ceramics are strongly dependent upon the density and the morphology of the specimens. The champion sample with the ratio of (Mg 0.95 Ni 0.05 ) 2 TiO 4 and CaTiO 3 of 0.92:0.08 showed an ε r value of 19.2, an Qf value of 108,200 GHz, and a τ f value of -4.8 ppm/°C, which may encourage (Mg 0.95 Ni 0.05 ) 2 TiO 4 ceramics to broaden the range of novel applications and match the requirements of 5G or next-generation communication systems.