The effect of high-energy ball milling on the electromechanical strain properties of Bi-based lead-free relaxor matrix ferroelectric composite ceramics

The crystal structure, ferroelectric, and electric-field-induced strain (EFIS) properties of Bi-based lead-free ferroelectric/relaxor composite materials are investigated. Bi1/2(Na0.82K0.18)1/2TiO3 as a ferroelectric material and 0.98Bi1/2(Na0.78K0.22)1/2TiO3‒0.02LaFeO3 as a relaxor were synthesized via conventional ceramic processing routes while the relaxor (matrix phase) was prepared via high-energy ball milling (HEBM) after calcination. The average particle size was decreased via HEBM treatment. As a result, a high d33* value of over 600 pm/V was obtained at 4 kV/mm for 30-min HEBM-treated composites. This demonstrates that HEBM treatment is effective in enhancing the strain properties of lead‒free piezoelectric composite materials.