セラミックス薄膜・基板接合体における薄膜の破壊強度

抄録

Indenter tests on a Al₂O₃ film-WC-Co substrate system using a Al₂O₃ sphere indenter were carried out to evaluate the fracture strength of the thin film coated on a substrate. Film thickness of the specimen was varied as 2.0, 4.0, 6.0μm, and two kinds of substrate with different hardness and sphere indenter with a daiameter of 16, 19, 25mm were used. The micro fracture strength was evaluated from the load at which a ring crack initiated. Initiation of a ring crack was detected using AE. The fracture strength of the film was evaluated using the micro fracture strength, the residual stress of the film, and the concept of effective area based on the Weibull distribution. Residual stress was measured by the X-ray diffraction method. It was shown that estimated fracture strength of the film a little increased with decreasing the indenter size, and the effect of the film thickness and the substrare hardness on the fracture strength of the film was hardly shown.