Effect of CeO2 on electrical properties, mechanical and thermal performance of 0.76Bi1/2Na1/2TiO3–0.24SrTiO3 lead-free piezoelectric ceramics

Abstract

Thermal and mechanical properties are important parameters for high-precision piezoelectric actuators. In this work, 0.76Bi_1/2Na_1/2TiO₃–0.24SrTiO₃-xwt% CeO₂ (abbreviated as BNST24-xCe) lead-free ceramics are found to have a large electrostrain of 0.176%, and a normalized strain (S_max/E_max) of 880 pm/V under an ultra-low driving field of 2 kV/mm. The BNST24-0.05Ce lead-free ceramics showed the representative parameters of Young’s modulus E ~ 142.1 GPa, Vickers indentation hardness H_v ~ 4.25 GPa, fracture toughness K_IC ~ 1.36 MPa·m^1/2, thermal conductivity λ ~ 1.392 W m⁻¹ k⁻¹, and coefficient of thermal expansion values CTE ~ 9.20 × 10⁻⁶ K⁻¹. These results indicate that these lead-free BNT-ST-based ceramics have excellent strain, thermal, and mechanical properties that meet the requirements for practical applications as piezoelectric actuators.