The stability and dielectric performance of BiNbO₄ prepared by citrate method assisting sintering process

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• 作者：Haifa Zhai ; Bei Chen ; Hongying Luo ; Haiqin Li ; Liuyang Zheng ; Jien Yang ; Hairui Liu and Zhiyong Liu
• 刊名：physica status solidi (a)
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：213
• 期：9
• 页码：2525-2530
• 全文大小：1537K
• ISSN：1862-6319

文摘

Low-temperature β phase BiNbO₄ powders (denoted as Low-β) were prepared by a citrate method using home-made water-soluble niobium precursors. The stability of Low-β was systematically investigated from the aspects including calcination temperature, incubation time, and stress existing in pellets. Pure Low-β can be obtained between 700 and 750 °C and the crystal evolution of Low-β has not completed yet, compared with high-temperature β phase. Low-β is kinetically stable and no phase transition occurs when increasing the incubation time below 750 °C. Above 750 °C, both the calcination temperature and incubation time can induce the abnormal phase transition from Low-β to α phase; also, stress existing in pellets can effectively activate the phase transition of Low-β. We can conclude that the Low-β is thermodynamically unstable, while in kinetics, Low-β is stable. The dielectric properties of BiNbO₄ ceramics were investigated to analyze the influence of phase of BiNbO₄ powders precursors, especially the effect of phase transition of Low-β. It's found that BiNbO₄ powders firstly calcined at 700 °C is the best precursor to prepare dense ceramics with uniform grain size and the dielectric permittivity and dielectric loss of BiNbO₄ ceramics prepared at 1000 °C is 56.6 and 0.001 at 10 kHz, respectively.