SYNTHESIS AND CHARACTERIZATION OF SB-SUBSTITUTED (K_0.5Na_0.5)NbO₃ PIEZOELECTRIC CERAMICS

Abstract

Lead-free piezoelectric ceramics (K 0.5 Na 0.5 )(Nb 1−x Sb x )O 3 +0.5 mol.%MnO 2 , where x = 0 ÷ 0.10, with single phase structure and rhombohedral symmetry at room temperature were prepared by conventional ceramic technology. The optimal sintering temperatures of compositions were within 1100 • -1140 • C. MnO 2 functions as a sintering aid and effectively improves the densification. The samples reached density from 4.26 g/cm 3 for undoped (K 0.5 Na 0.5 )NbO 3 to 4.40 g/cm 3 for Mn/Sb 5+ co-doped ceramics. The co-effects of MnO 2 doping and Sb 5+ substitution lead to significant improvement in dielectric and piezoelectric properties: ε at the T c increased from 6000 (KNN) to 12400 (x = 0.04), d 33 = 92 ÷ 192 pC/N, k p = 0.32 ÷ 0.46, k t = 0.34 ÷ 0.48.

Enhanced Piezoelectric Properties and Thermal Stability in the (K0.5Na0.5)NbO3:ZnO Lead‐Free Piezoelectric Composites

“…Generally, the piezoelectric coefficient d 33 can be improved at the expense of lowing T C and vice versa. Among the large number of KNN‐based lead‐free materials, d 33 can be improved by moving T O‐T or T R‐T to room temperature by various chemical substitutions, such as 0.948KNN‐0.052LiSbO 3 , 0.99KNN‐0.01BiFeO 3 , and (K 0.5 Na 0.5 )(Nb 0.93 Sb 0.07 )O 3 , however, the T C is decreased at different magnitude. Here, the present composites of KNN: x ZnO exhibit enhanced piezoelectric coefficient d 33 but with well‐maintained high T C .…”

Broadband Dielectric Investigation of Sodium Potassium Niobate Ceramic Doped 8% of Antimony

“…The main problem with KNN is sintering: it is difficult to obtain well-sintered KNN ceramic using an ordinary sintering process because of the high volatility of alkaline elements at high temperatures [6]. To produce well sintered, dense ceramic with one phase there was added 0.5 mol % MnO 2 as sintering aid.…”

ZnO Doping Effects on Piezoelectric and Ferroelectric Characteristics of Lead-free CuO Doped Na0.5K0.5Nb0.97Sb0.03O3Piezoelectric Ceramics

“…24 Dambekalne and Antonova studied the (Na,K)(Nb,Sb)-MnO 2 system and found that MnO 2 functions as a sintering aid and effectively improves the densification. 25 Wu and Xiao researched the (Na,K)(Nb,Sb)-CaTiO 3 system; their results show that CaTiO 3modified (Na,K)(Nb,Sb) lead-free piezoelectric ceramics form a stable solution with an orthorhombic structure and that the piezoelectric properties of the ceramics strongly depend on the poling temperature. 26 Park and Seo investigated the 2% CuO doped in the (Na,K)(Nb,Sb) system.…”