Chromium nitride films synthesized by radio-frequency reactive ion plating

Abstract

Cr–N films were synthesized successfully on the stainless steel and the high-speed steel plates by rf reactive ion plating. Cr was evaporated from an electron beam evaporator into the N2 or NH3 gas plasma at the pressure of the order of 10–2 Pa. The optimum net rf power to synthesize was about 200 W. The amount of Cr and N atoms contained in the synthesized layer were measured by Auger electron spectroscopy. The crystal structure of the layer was analyzed by x-ray diffraction and reflection high energy electron diffraction. The resulting Cr–N films formed by rf reactive ion plating had two types of crystal structures composed of β-Cr2N and CrN, and the type of structure was able to be controlled easily by the ion plating conditions. The structure of the hardest film was found to be β-Cr2N (hexagonal structure) by micro-Vickers method. All the films synethsized under the various conditions by the method were observed to be composed of small size grains with microcracks.