Effect of nitrogen flow ratios on the microstructure and properties of (TiVCr)N coatings by reactive magnetic sputtering

Abstract

The present paper reports the influence of growth conditions on the characteristics of (TiVCr)N coatings prepared by dc reactive magnetron sputtering at various N(2)-to-total (N(2) + Ar) flow ratios, R(N). The crystal structures, microstructure, and mechanical, electrical and optical properties under the R(N) were characterized. Results indicate that the TiVCr alloy and nitride coatings exhibited a single body-centered cubic type (BCC) and a face-centered cubic (FCC) solid solution structure, respectively. As the R(N) increases, the preferred orientation (TiVCr)N coatings changed to (2 0 0). The grain size also had a significant increase. The microstructure of the coatings obviously changed from a porous to a compact and dense columnar structure. Accordingly, the physical properties of the coatings were improved due to the densification of the structure. The hardness of the (TiVCr)N was enhanced to about 15 GPa, and the electrical resistivity was lowered to 10,000 mu Omega-cm. (C) 2011 Elsevier B.V. All rights reserved.