电场对铁电陶瓷压痕裂纹的作用

EFFECTS OF ELECTRIC FIELD ON INDENTATIONCRACKS OF PZT FERROELECTRIC CERAMICS

研究了极化锆钛酸铅 (PZT - 5 )铁电陶瓷压痕裂纹在硅油中电场作用下的扩展过程 .结果表明 ,当外加电场强度大于裂纹瞬时扩展临界电场强度 (Eip=5 2 5kV/cm) ,压痕裂纹能够发生瞬时扩展 ,继续保持恒电场 ,裂纹会继续扩展 .当外加电场强度小于裂纹瞬时扩展临界电场强度 ,裂纹不发生瞬时扩展 ,但保持恒定电场 ,裂纹会发生滞后扩展 .同时 ,裂纹扩展量显示各向异性 ,与垂直于电场方向裂纹相比 ,平行于电场方向的裂纹扩展量很小 .

Propagation process of indentation cracks in silicon oil with an applied electric field for poled PZT-5 ferroelectric ceramics has been investigated.The results showed that indentation cracks could instantaneously propagate in silicon oil with an applied electric field which was higher than critical electric field for instantaneous propagation (E ip =5.25 kV/cm) and the lengths of cracks could increase with increasing the time to keep sustained applied electric field.When applied electric field was lower than E ip ,the cracks could not propagate,but if keep sustained electric field,delayed propagation might occur.Moreover,the anisotropy of cracks propagation has been measured.The propagation lengths of the cracks parallel to applied electric field direction are shorter than that of perpendicular to applied electric field direction.