Microwave hybrid sintering of 0.95(Mg0.95Zn0.05)TiO3-0.05CaTiO3 ceramics and its microwave dielectric properties

Microwave dielectric ceramic powder of 0.95(Mg0.95Zn0.05)TiO3-0.05CaTiO(3) (MCT) has been prepared by solid-state reaction method through single-step calcination at 1150 degrees C. The green bodies prepared from the calcined powder have been sintered by conventional, susceptor-aided, and hybrid microwave sintering techniques followed by annealing. XRD of calcined and sintered ceramics show (Mg,Zn)TiO3 as a major phase with CaTiO3 as a minor secondary phase. Fractographs of fired ceramics obtained by SEM show similar features in conventional and hybrid microwave types of sintering. Microwave dielectric properties such as relative permittivity(epsilon(r)), temperature coefficient of resonant frequency(tau(f)), and unloaded quality factors (Q(u)) for conventional sintered at 1325 degrees C for 4 h are-epsilon(r)similar to 19.8, tau(f)< -6 ppm/degrees C and Q(u).f 69,600 GHz at 6 GHz. Ceramics obtained through susceptor-aided microwave sintering at 1325 degrees C for 4 h show poor fired density. But ceramics got by microwave-hybrid sintering (resistive + microwave) at the same temperature show epsilon(r)similar to 20.6, Q(u).f similar to 81,600 GHz at 6 GHz and tau(f)similar to-6.9 ppm/degrees C. The effect of hybrid microwave sintering on the dielectric properties of MCT ceramics is found to be more subtle than microstructural.

Automated summary

Microwave dielectric ceramic powder of 0.95(Mg0.95Zn0.05)TiO3-0.05CaTiO(3) (MCT) was prepared using solid-state reaction method and different sintering techniques were employed. The hybrid microwave sintering technique showed better dielectric properties compared to other techniques.