Antimony Tuned Rhombohedral‐Orthorhombic Phase Transition and Enhanced Piezoelectric Properties in Sodium Potassium Niobate

Abstract

It has been reported that the rhombohedral–orthorhombic low‐temperature polymorphic phase transition in (Na,K)NbO3 can be tuned close to room temperature by substituting Sb for Nb, such that enhanced piezoelectric properties are induced based on the theory of two‐phase coexistence. A diagram of phase structures changing with Sb content and temperature has been generalized for (Na,K)(Nb,Sb)O3 (NKNS) compositions. The thermal stability of piezoelectric properties of NKNS ceramics was evaluated considering the existence of successive phase transition above room temperature. The microstructure, dielectric, and ferroelectric properties of NKNS ceramics were discussed from a crystallographic point of view.

Microstructure and piezoelectric properties of Ho2O3 doped (K0.4Na0.6)0.95Li0.05Nb0.95Sb0.05O3 lead-free ceramics near the rhombohedral–orthorhombic phase boundary

“…1c, d that the solid solutions are of orthorhombic symmetry when x B 0.6. The split {100} and {200} peaks become one peak when x C 0.8, confirming that the orthorhombic and rhombohedral phase coexistence can be formed [25][26][27][28].…”

“…Other attempts have been made to design KNN-based ceramics with additives (BaZrO 3 , CaZrO 3 , BiScO 3 ) by shifting rhombohedral-orthorhombic phase transition temperature (T O-R ) toward room temperature [17][18][19]. This rhombohedralorthorhombic phase coexistence zone is still a polymorphic phase boundary (PPB), rather than a MPB, for its temperature dependent behavior [20][21][22][23].…”

Influence of K/Na ratio on phase structure and electrical properties of 0.96 (K x Na1−x ) NbO3-0.04 (Bi0.5Na0.5) ZrO3 lead-free ceramics

“…However, those KNNbased ceramics with Sb will be harmful to the human health because of its light toxicity, and moreover their T C will be rapidly dropped by doping Sb 5+ [32]. In addition, a pure KNN ceramic modified by (Bi,M) ZrO 3 also possesses a relatively poor d 33 [29,30].…”

Polymorphic phase transition-induced electrical behavior of BiCoO3-modified (K0.48Na0.52)NbO3 lead-free piezoelectric ceramics

“…In contrast, the R-O phase transition temperature (T R-O ) at a low temperature has been almost neglected for the KNN system. More recently, it has been reported that the T R-O phase transition below room temperature of (Na, K) (Nb, Sb) O 3 , KNN-BaZrO 3 and KNN-BiScO 3 ceramics can be tuned close to room temperature, and better piezoelectric properties are induced by the theory of two-phase coexistence [11][12][13].…”