Mechanical, Oxidative Properties, and Wear Behaviors of CrAlSiN Coatings Applied on Cutting Tools

Abstract

In this study, we investigated the mechanical and oxidation properties of WC-Co and CrAlSiN-coated turning inserts and analyzed their wear behaviors. CrAlSiN films were synthesized  by radio-frequency magnetron sputtering from alloy targets. X-ray diffraction analysis indicated that all the prepared films have a cubic structure without any hexagonal phase. The average microhardness increased from 27 GPa for WC-Co up to 37 GPa for CrAlSiN, whereas the average frictional coefficient decreased from μ＝0.50 for WC-Co down to μ＝0.17 for CrAlSiN. During dynamic oxidation, the maximum exothermic peak in the differential thermal analysis curve was observed at 549 ℃ for WC, the main component of WC-Co, and at 1384 ℃ for CrAlSiN. Corresponding to the exothermic reactions, the mass gain determined by thermogravimetric analysis increased from 23% for WC to 6% for CrAlSiN. The wear behaviors of WC-Co and CrAlSiN-coated inserts were verified through the in situ measurement of cutting resistance and the observation of their flank wear after cutting tests. The minimum cutting resistance and width of flank wear were confirmed for CrAlSiN-coated inserts.