Preparation and enhanced electric-field-induced strain of textured 91BNT–6BT–3KNN lead-free piezoceramics by TGG method

Abstract

oriented 0.91Bi1/2Na1/2TiO3–0.06BaTiO3–0.03(Na,K)NbO3 (BNT–BT–KNN) lead-free piezoceramics were fabricated by templated grain growth method. A high grain orientation degree (Lotgering factor F is 83 %) was achieved with 5 wt% Bi1/2Na1/2TiO3 (BNT) template content and a maximum strain value of 0.226 % was observed, which was 48.7 % higher than that of randomly oriented samples. However, too much BNT template will result in composition deviation from morphotropic phase boundary of BNT–BT–KNN system and disruption of the non-polar phase at zero electric field. All textured samples with 1–10 wt% template addition showed enhanced strain and large signal piezoelectric coefficient $$d_{33}^{*}$$ without disrupting the non-polar phase at zero electric field. The enhanced electric-field-induced strain of the textured sample was primarily attributed to the facilitated phase-transition, which formed a long-range ferroelectric order along the direction.