Synthesis and evaluation of chromium nitride films in magnetron sputtering system with application to the substitution of hard chromium

In order to studypossibility of substitution of hard chromium coatings with new coatings،chromium nitride thin films prepared in a sputtering system. Results showed that microstructure of coatings strongly depends on partial pressure of reactive gas. With increasing partial pressure of reactive gas in system at first nitride phase forms when coatings lose their crystalline order and become amorphous with increasing partial pressure of reactive gas. Change of N2/Ar ratio leads to a decrease of grain size but does not affect the lattice parameter so much. Plastic hardness of samples increased with increasing partial pressure of reactive gas which can be attributed to the grain size of the samples and Hall-Pech relation. This relation did not work for the sample with the highest nitrogen which was attributed to its very fine grain and increased grain boundary defects. Study of oxidation resistance of CrN film with the highest hardness value showed that this coatings completely oxides at 600 oC and completely separates from the substrate at 800oC. It seems that it is possible to get CrN films with better mechanical properties than that of hard chromium with precise control of deposition conditions and this coating can replace hard chromium from the view point of mechanical properties. However، this coating cannot replace hard chromium from the view point of oxidation resistance.