The effects of Li2CO3 addition on microstructural and piezoelectric properties of lead-free (Ba,Ca)(Ti,Zr)O3 piezoceramics sintered in either air or a reducing atmosphere were investigated. A reducing atmosphere was maintained by controlling the oxygen partial pressure with a suitable mixture of Ar, H2, and CO2 gases. Li2CO3 addition promoted grain growth in the ceramic samples, which were highly polarized following poling treatment. An optimal amount of Li2CO3 was necessary for maintaining controlled grain growth and high density during sintering. The resulting ceramics exhibited high electrical resistivity and improved piezoelectric properties. The dielectric properties of the ceramics prepared with Li2CO3 exhibited a similar dependence on temperature, regardless of the sintering atmosphere or amount of Li2CO3 added. Even though the amount of added Li2CO3 ranged from 0.3 to 9 mol%, the residual Li content in the ceramics after sintering was approximately 0.1 mol%. The sintered bodies exhibited good electrical resistivity (>1012 Ω cm) and relatively high piezoelectric constants (d 33) of ∼400 pC/N.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)