Effects of modified-process on the microstructure, internal bias field, and activation energy in CuO-doped NKN ceramics

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• 作者：Song-Ling Yang^a ; Cheng-Shong Hong^b ; Cheng-Che Tsai^c ; Yi-Cheng Liou^d ; Sheng-Yuan Chu^a ; ^e ; ^{chusy@mail.ncku.edu.tw}
• 关键词：Two-step calcination process ; Microstructure ; Oxygen vacancies ; Internal bias field ; Activation energy
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：July, 2012
• 卷：32
• 期：8
• 页码：1643-1650
• 文件大小：1463 K

摘要

In this study, (Na_0.5K_0.5)NbO₃ + xCuO (NKNCx, where x = 0-1 mol%) were separately prepared using the two-step calcination process (BO method) and a conventional mixed oxide method (MO method). The microstructure of NKNCx ceramics prepared using the MO method exhibited obviously inhomogeneous microstructure. In contrast, the BO method improved the compositional homogeneity as well as the electrical properties. A high Q_m value of 2100 was obtained for NKNCx ceramics prepared using the BO method. The ceramics prepared using the BO method exhibited the formation of more oxygen vacancies, resulting in an increase in the internal bias field. The value for the activation energy of the samples supports the presence of oxygen vacancies. The bulk density, dielectric loss, k_p, Q_m, d₃₃ and 蓻₃₃^T/蓻₀ of the NKNCx ceramics prepared using the BO method were 4.488 g/cm³, 0.15%, 41.5%, 2100, 95 pC/N and 280, respectively.