Low-frequency internal friction of lead metaniobate ceramics

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.