Identification of Phase Boundaries and Electrical Properties in Ternary Potassium-Sodium Niobate-Based Ceramics

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• 作者：Xiang Lv ; Jiagang Wu ; Shuang Yang ; Dingquan Xiao ; Jianguo Zhu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：July 27, 2016
• 年：2016
• 卷：8
• 期：29
• 页码：18943-18953
• 全文大小：1041K
• 年卷期：0
• ISSN：1944-8252

文摘

A large piezoelectric constant (d₃₃) of ∼480 pC/N was attained in new ternary (1–x–y)K_0.5Na_0.5Nb_0.96Sb_0.04O₃-xBaSnO₃-yBi_0.5Na_0.5ZrO₃ ceramics by forming rhombohedral-orthorhombic-tetragonal (R-O-T) phase boundary using the variations of x and y, and such a phase boundary was successfully confirmed by the convergent beam electron diffraction (CBED) patterns. For (1–x)K_0.5Na_0.5Nb_0.96Sb_0.04O₃-xBaSnO₃, the orthorhombic (O) phase is well-maintained for 0 ≤ x ≤ 0.015, and both the R and T phases can be introduced to (0.99–y)K_0.5Na_0.5Nb_0.96Sb_0.04O₃-0.01BaSnO₃-yBi_0.5Na_0.5ZrO₃ with y = 0.025–0.04 by simultaneously tailoring their compositions (x and y); then, R-O-T multiphases can be well-established. The CBED patterns strongly support the existence of R-O-T multiphases in the ceramics with y = 0.035. When the phase transitions endure from O to R-O-T, their piezoelectric activity endures a leapfrog development from ∼165 to ∼480 pC/N. In the region of the R-O-T phase boundary, a large d₃₃ of ∼480 pC/N was attained in the ceramics with x = 0.01 and y = 0.035. In addition, the ceramics with x = 0.01 and y = 0.04 possess a high strain of ∼0.274% due to the multiphases coexistence. According to the variations of dielectric and ferroelectric properties, the enhancement in ε_r and P_r plays a part in the improved d₃₃ except for the R-O-T phase boundary. We believe that the (K, Na)NbO₃ ternary systems can be used to promote piezoelectric activity by forming new phase boundaries.