Structural and Mechanical Properties of (Al,Cr)N and (Al,Cr)SiN Coatings Reactively Sputter Deposited

Abstract

AlCrN and AlCrSiN coatings were deposited on M2 steel by cosputtering of metallic Al-Cr (70–30 at.-%) and Si targets in reactive argon–nitrogen gas mixtures. The Si content in the film varied from 0 to 1.7 at.-%, as a function of the current applied on the Si target. The properties of these films have been determined by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). Nanohardness test (NHT) and scratch tests have been used to determine their mechanical properties. All the coatings are amorphous (or nanocrystallised) with a dense glassy morphology and present a good adhesion. The mechanical tests have clearly shown the effect of the addition of Si on the properties of the coatings. Hardness and Young's modulus increase with the silicon content whereas the friction coefficient decreases.