Volume 8, Issue 7 (July 2011)
Effect of Additional Elements on Microstructure and Properties of CrN Coatings
CrMoN and CrWN coatings were deposited using closed field unbalanced magnetron sputter ion plating system. The microstructure, preferred orientation, and morphology of coatings were determined by x-ray diffraction analysis and SEM observation. The influences of additional elements on the microstructure, adhesion, mechanic, and tribological properties have been investigated. XRD Results showed that preferred orientation of CrMoN and CrWN coatings obviously changed compared with that of the pure CrN coating. All of the new hard coatings exhibited excellent adhesion due to the gradient interface layer design. By introducing Mo and W elements into the CrN-based structure, the coating hardness had an obvious improvement in comparison with pure CrN coatings. Results also showed the wear resistance of CrMoN and CrWN coatings increased clearly. The steady-state dry friction coefficients of the new coatings measured against a WC–6% Co ball are about 0.3, which were significantly decreased from 0.5 of pure CrN coaing. It is expected that these advantageous properties can enable these new hard coatings for a wide range of applications such as dry high-speed machining.