Stress corrosion cracking and its anisotropy of a PZT ferroelectric ceramics

It is known that some types of ceramics, like Al2O3 and ZrO2, undergo stress corrosion cracking (SCC) or static fatigue fracture under static loading, ever in a rela-tively mild environment, such as moist atmosphere or water at room temperature, which leads to a time-dependent fracture1—4]. For a transmission electron microscopy specimen of YBa2Cu3O7-x ceramics superconductor, SCC induced by residual stress can occur in an atmosphere with low moisture content5]. For a lead zirconate ti…

Stress corrosion cracking and its anisotropy of a PZT ferroelectric ceramics

Stress corrosion cracking (SCC) of a PZT ferroelectric ceramics in various media, such as moist atmosphere, silicon oil, methanol, water and formamide, and its anisotropy have been investigated at constant load test using a single-edge notched tensile specimen. The results showed that SCC could occur in all media, and the threshold stress intensity factor of SCC in water and formamide, K_ISCC, revealed anisotropy. The K_ISCC for poling direction parallel to the crack plane, K^a_ISCC was greater than that perpendicular to the crack plane, K^b_ISCC similar to the anisotropy of fracture toughness K_IC; however, the anisotropy factor of K_ISCC, which was K^a_ISCC/K^b_ISCC=1.8 (in formamide) and 2.1 (in water), was larger than that of K_IC, which is K^a_IC/K^b_IC=1.4. The stress-induced 90° domain switching causes the anisotropy of K_IC and K_ISCC, besides, the resistance of SCC also has anisotropy.