偏铌酸铅陶瓷低频内耗的研究

Low-Frequency internal Friction of Lead Metaniobate Ceramics

用低频倒置扭摆对改性偏铌酸铅铁电陶瓷的内耗进行了研究．在新加工的样品中发现了六个内耗峰，分别位于７０℃（Ｐ１峰）、 ９０℃（Ｐ２峰）、２００℃（Ｐ３峰）、２６０℃（Ｐ４峰）、４３０℃（Ｐ５峰）和５１０℃（Ｐ６峰）处．对引起Ｐ３、Ｐ１、Ｐ２和Ｐ４峰的物理机制进行了详细探讨．分析结果表明，Ｐ３峰的本质是一定化的 Ｄｅｂｙｅ弛豫内耗峰。相应的激活能和指前因子分别为１．０１４Ｖ和 ２．４×１０－１４ｓ．它源于氧空位与畴壁的相互作用． Ｐ１、 Ｐ２和 Ｐ４峰与试样的切割加工密切相关，可归结为点缺陷与位错的交互作用．

The internal friction Q-1 of Lead Metaniobate ceramics was investigated by inverted torsion pendulum. Six internal friction peaks, with their location around 70℃(P1), 90℃(P2), 200℃(P3), 260℃(P4), 430℃(P5) and 510℃(P6), respectively,were observed in a freshly-worked PbNb2O6 ceramics. The mechanisms for P3, P1, P2 and P4 were analyzed in detail. P3 is a broadened Debye relaxation peak in nature, and its corresponding activation energy and pre-exponential factor are 1.01eV and 2.5x10-12s, respectively. Thir peak is attributed to the interaction between domain walls and oxygen vacancies. P1, P2, and P4 are clearly related to the working processes. They can be caused by the interaction between dislocations and point defects.