Enhancement in the microstructure and the strain properties of Bi1/2(Na,K)1/2TiO3-based lead-free ceramics by Li substitution

The effects of Li substitution on the crystal structure and the strain properties of Bi0.5-(Na0.82K0.18)0.5(Ti0.95Sn0.05)O3 ceramics have been investigated. Li substitution enhanced the grain growth and densification, as well as the electric-field-induced strain (EFIS). Without Li substitution, the EFIS was 0.31% under a dc field of 6 kV/mm. However, the EFIS was enhanced to 0.39% when 4 mol% Na was replaced with Li, resulting in a normalized strain (Smax/Emax) of 646 pm/V. The enhanced strain could be attributed to the increased flexibility in the lattice caused by simultaneous substitutions with both A-site Li ions and B-site Sn ions.