Influences of sintering aids on discontinuous grain growth and properties in BaTiO ₃ ‐based ferroelectric ceramics

Abstract This work studies the influences of sintering aids on discontinuous grain growth (DGG) and corresponding grain size effect in Ba(Ti _0.8 Zr _0.2 )O ₃ ceramic. When sintering temperature ( T _S ) is 1280–1340°C, the DGG phenomenon is observed with little change in phase structure, and grains all grow from several to tens of micrometers. Adding LiF can decrease the temperature span ( T _span ) of DGG from 20°C to 10°C due to the high mobility of Li ⁺ ; however, adding Li ₂ CO ₃ extends T _span from 20°C to 40°C since it decomposes and releases gas and then hinders the DGG process. Adding SiO ₂ and B ₂ O ₃ decreases the critical T _S of DGG by about 20–30°C due to their lower melting point or eutectic temperature. A higher critical T _S or a narrower T _span generally results in smaller grains and lower density before DGG, while can induce larger grains and higher dielectric/ferroelectric properties after DGG. Obvious dielectric diffuseness behavior is observed after adding Li ₂ CO ₃ or B ₂ O ₃ due to the smaller grains or more pores. The variation in properties is consistent with the grain size change after adding sintering aids. This work shows a fundamental understanding of sintering aids' influences on DGG and provides guidance for controlling microstructure and properties in polycrystalline ceramics.