Synergic and competitive effect of A-site substitution on structure and electric property in BaTiO3-based ceramics

Abstract

Sites engineering has been extensively investigated in BaTiO3-based lead-free materials. Although the effect of A or B site substitution on structure and electric properties have been researched adequately, the synergic and competitive impacts of doping element have received little attention, which has become an urgent issue for further optimizing performance. Here, three groups BT-based ceramics [0.6(Ba0.9Ca0.1)TiO3-0.4Ba(Sn0.2Ti0.8)O3, B(Ca)TS, 0.6(Ba0.9Ca0.05Sr0.05)TiO3-0.4Ba(Sn0.2Ti0.8)O3, B(Ca,Sr)TS, and 0.6(Ba0.9Sr0.1)TiO3-0.4Ba(Sn0.2Ti0.8)O3, B(Sr)TS] are synthesized by normal sintering, revealing the synergic and competitive mechanism of A site doping on structure and properties. The effect of Ca2+ and Sr2+ are quite different on the structure, especially the phase structure and grain size, and the evolution of electric properties (e.g., d33, Strain, and Temperature stability) results from structure caused by the synergic and competitive effect of Ca2+ and Sr2+. For example, a large d33 (∼950 pC/N) is obtained in B(Sr)TS due to its closer R-O-T phase structure compared to B(Ca)TS and B(Ca,Sr)TS ceramics, which is superior to some previous BT-based studies. Therefore, exploring of doping mechanism can further tune the microscopic structure and thus enhance electric properties, accelerating the practical process of lead-free ceramics.