Applied Surface Science, Vol.452, 210-216, 2018
Surface failure analysis of AlCrN coating on WC substrate subjected to high-temperature oxidation in glass-molding machine
In this study, a surface failure analysis was performed on an aluminum chromium nitride (AlCrN) coating formed on a tungsten carbide (WC) substrate used in a glass-molding machine and subjected to oxidation at elevated temperatures. Several pinholes were observed in the coating, with the coating surface exhibiting discoloring. The microstructures, crystalline structures, and elemental compositions of the coating and substrate were observed using scanning electron microscopy, X-ray diffraction analysis, and X-ray fluorescence spectroscopy. In particular, the phenomena occurring near the coating/substrate interface were examined using focused ion beam milling and grazing incidence X-ray diffraction analysis. The pinholes-containing coating area consisted of an oxide, with the composition of the coating being inhomogeneous. Further, voids were present near the substrate/coating interface, with some of the coating components being detected in the substrate as well. It was concluded that the Al/Cr atomic ratio of the AlCrN coating was not constant, owing to the oxidation of the coating at the elevated temperatures. (C) 2018 Elsevier B.V. All rights reserved.