Development of chromium nitride coatings substituting titanium nitride

Abstract

The deposition of chromium nitrides by reactive magnetron sputtering on machine parts seems to be very promising, because the mechanical properties are similar to those of TiN hard coatings. Especially the corrosion resistance of CrN is an interesting aspect related to the known problems of TiN films. The presented research deals with the deposition of CrN films by using r.f.-magnetron sputtering units. Starting with common deposition parameters for titanium nitride and a variation of the deposition parameters, partial pressure and bias voltage, chromium nitride coatings are deposited on steel substrates. The results show that the reactive sputtering process of CrN is more sensitive to minor changes of the adjustable deposition parameters and the related plasma conditions than that of TiN. The deposition of CrN allows the production of coatings with a wide field of properties but only within small windows of deposition parameters, especially when sputtering Cr 2N films. The characterization of the coatings by their basic properties, such as thickness, hardness, adhesion, phase analysis and residual stress, indicates possibilities and limits of CrN coating systems.