In-situ high temperature X-ray diffraction study of Cu/Al₂O₃ interface reactions

In-situ experiments on the Cu/Al₂O₃ interface reaction were carried out with a high temperature X-ray diffractometer capable of measuring the X-ray diffraction pattern in 1-2 s using an imaging plate. The kinetic formation processes of the interface reaction layer were measured by short-period exposure experiments with a high temperature X-ray diffractometer. CuAlO₂ was formed at the Cu/Al₂O₃ interface from 1411 to 1467 K in air. The formation of CuAlO₂ obeyed the parabolic rate law. The value of the activation energy suggests that the diffusion of O (included in Cu₂O) through CuAlO₂ controls the rate of formation. The results of thermal expansion coefficient measurements suggest that when a sample is cooled to room temperature, the magnitude of stress on Al₂O₃ caused by CuAlO₂ and CuO is smaller than that caused by Cu₂O.