Effects of Na/K ratio on the phase structure and electrical properties of NaxK1-xNbO3 lead-free piezoelectric ceramics
来源期刊：Rare Metals2010年第2期
论文作者：ZHANG Qian, ZHANG Boping, Li Haitao, and SHANG Pengpeng School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing , China
文章页码：220 - 225
摘 要：Lead-free piezoelectric NaxK1-xNbO3（x = 0.3-0.8）（NKN） ceramics were fabricated by normal sintering at 1060°C for 2 h.Microstructures and electrical properties of the ceramics were investigated with a special emphasis on the influence of Na content.The grain size of the produced dense ceramic was decreased by increasing Na content.A discontinuous change in the space distance was found at the composition close to Na0.7K0.3NbO3 ceramic, which indicates the presence of a transitional composition between two different orthorhombic phases, which is similar to the behavior of morphotropic phase boundary（MPB） in NaxK1-xNbO3 ceramics.Such MPB-like behavior contributes to the enhanced piezoelectric coefficient d33 of 122 pC/N, planar-mode electromechanical coupling coefficient kP of 28.6%, and dielectric constant εr of 703, respectively for the Na0.7K0.3NbO3 ceramic.Cubic temperature TC and the transitional temperature TO-T from orthorhombic to tetragonal phase are observed at around 420°C and 200°C, respectively.
ZHANG Qian, ZHANG Boping, Li Haitao, and SHANG Pengpeng School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
摘 要：Lead-free piezoelectric NaxK1-xNbO3（x = 0.3-0.8）（NKN） ceramics were fabricated by normal sintering at 1060°C for 2 h.Microstructures and electrical properties of the ceramics were investigated with a special emphasis on the influence of Na content.The grain size of the produced dense ceramic was decreased by increasing Na content.A discontinuous change in the space distance was found at the composition close to Na0.7K0.3NbO3 ceramic, which indicates the presence of a transitional composition between two different orthorhombic phases, which is similar to the behavior of morphotropic phase boundary（MPB） in NaxK1-xNbO3 ceramics.Such MPB-like behavior contributes to the enhanced piezoelectric coefficient d33 of 122 pC/N, planar-mode electromechanical coupling coefficient kP of 28.6%, and dielectric constant εr of 703, respectively for the Na0.7K0.3NbO3 ceramic.Cubic temperature TC and the transitional temperature TO-T from orthorhombic to tetragonal phase are observed at around 420°C and 200°C, respectively.
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