Contamination-free solid-state synthesis of BaZrO3 powder via sonochemical mixing of BaCO3 and ZrO2

Abstract

We present a comparative analysis of BaZrO₃ powders and ceramics synthesized through solid-state reactions, using stoichiometric mixtures of BaCO₃ and ZrO₂ prepared either by ball-milling (BM) or sonochemical (SC) mixing. BaZrO₃ powders synthesized through 5 min of sonochemical mixing exhibited properties nearly indistinguishable from those produced by 24 h of ball-milling and any potential Zr contamination from the collision between ZrO₂ balls and ZrO₂ raw powder could not be identified in the powder form. However, after sintering, clear differences were observed between BM and SC ceramics in terms of microstructure, dielectric properties, and electrical characteristics, all of which can be attributed to the effect of oxygen vacancy from Schottky defects, stemming from excess Zr contamination in the BM ceramic. Our results confirm that sonochemical mixing provides precise control over the designed composition in the solid-state synthesis of oxide powders, while saving the process time.