In situ high temperature x-ray diffraction study of Ni/SiC interface reactions

摘要

In situ experiments on the Ni/SiC 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 in short-period exposure experiments with the apparatus. The time-temperature phase diagram of Ni/SiC in N sub 2 was determined. delta -Ni sub 2 Si and theta -Ni sub 2 Si (high temperature phase of delta -Ni sub 2 Si) were formed at the Ni/SiC interface between 1072-1418K in N sub 2 . The formation of delta -Ni sub 2 Si obeyed the parabolic rate law. The value of the activation energy suggests that the diffusion of Ni through delta -Ni sub 2 Si controls the rate of formation. The results of thermal expansion coefficient measurements suggest that when a sample is cooled to room temperature, compression caused by delta -Ni sub 2 Si occurs on SiC. (Authors note relevance to high strength composites and to electronic device fabrication.)