Multi-component nitride coatings derived from Ti–Al–Cr–Si–V target in RF magnetron sputter

Abstract

The nitride coatings comprised of various constituents Ti, Al, Cr, Si, V were deposited on mild steel by RF magnetron sputtering process. The Ti–Al–Cr–Si–V multi-component target introduced in this study was fabricated by conventional metallurgical method with atomic ratio of each selected element at 1:1:1:1:1. Different coatings were fabricated under various working pressure by adjusting nitrogen flux from 0 to 30 sccm during sputtering. Compositions of the target and the sputtered films were measured by FE-EPMA, and both of them were near equi-molar. According to XRD patterns, amorphous structures were revealed for the metallic and nitride 1 ( N = 46.2 at.%) films. The face centered cubic phases were exhibited by nitride 2 and nitride 3 with nitrogen contents around 58 at.%. Two different surface morphologies were investigated by the AFM, and they were consistent with the nanostructure observed in the XRD pattern. In addition, microhardness of the nitride coatings was measured by nanoindentation, and hardness higher than 30 GPa was exhibited in both nitride 2 and nitride 3. The microhardness test provided evidence that the multi-component nitride could be a potential candidate coating for tool steel.