Deformation of Hard Coatings at Elevated Temperatures

The elevated temperature performance of a wide range of chromium nitride-based hard coatings was evaluated using in situ micro-compression in the scanning electron microscope. This allows the first direct measurement of the high temperature compressive strength, rather than the hardness, of such coatings. The microstructure of the coatings was analyzed using X-ray diffraction and focused ion beam cross sectioning followed by electron microscopy. Micropillars were examined using electron microscopy before, during and after compression. Trends in deformation behavior and failure stress with temperature are discussed in relation to the coatings' microstructures and their room temperature mechanical properties.