Sinterability and Dielectric Properties of Strontium Zirconate Oxide with Al Substitution for Zr

Abstract

The effect of Al substitution for Zr on the sinterability of SrZrO₃ powders was studied by means of XRD, BET, and SEM. The density of SrZrO₃ increased with increasing amount of Al, and the sinterability of SrZrO₃ was greatly improved by the substitution. The highest density of 94% was achieved for SrAl_0.02Zr_0.98O_2.99ceramics prepared after calcining at 1300°C and firing at 1600°C for 3 h. The analysis of isothermal shrinkage curves exhibited that the diffusion mechanism changed from grain-boundary to volume diffusion by the formation of oxygen vacancy. The dielectric constant of the present SrZr_1-xAl_xO_3-δ ceramics increased to around 45 from 20 of pure SrZrO₃ ceramics in the frequency range 1 kHz to 100 kHz.