SEM determination of optimum processing conditions for microwave dielectrics in the (Ca,Sr,Ba) zirconate system

Abstract

Ceramic components for microwave applications, such as dielectric resonators, typically must possess low dielectric loss (high Q), high dielectric constant (εr) and small temperature coefficient of permittivity (τε). Non-stoichiometric CaZrO3 doped with Sr and Ba has been shown to possess these necessary characteristics Compact and highly reliable microwave components can, therefore, be fabricated using these materials. In this study, the effect of heat-treatment on the final microstructure was investigated.A chemical solution technique was used to synthesize powders of the composition Ca0.965(Sr0.030Ba0.005)Zr0.990O4 Chemical preparation methods offer the advantages of precise stoichiometric control, atomistic homogeneity, high purity, and fine particle size of the resultant powders. Appropriate amounts of the nitrate salts in aqueous solution were mixed to prepare the desired composition. The solution was converted to a powder by evaporation and calcined at 600°C and 800°C for 2 hours.