Characterization of Cr–Al–C and Cr–Al–C–Y films synthesized by High Power Impulse Magnetron Sputtering at a low deposition temperature

Abstract

A focus point in this work was the study of the influence of a low substrate temperature, as well as the minor addition of Y (0.1–0.3at.%), on the formation of the stable Cr2AlC–MAX (ternary alloy with general formula Mn+1AXn: M=early transition metal, A=A-Group element, mostly IIIA or IVA, X=C or N, n=1–3) phase. The coatings, deposited by High Power Impulse Magnetron Sputtering, consisted of a mixture of disordered solid solution (Cr,Al)2Cx and ordered Cr2AlC–MAX phase. All deposited coatings without and with 0.1–0.3at.% Y addition were polycrystalline, and showed (110) texture and a columnar morphology. The measured strong lattice distortions along with the existence of the texture in the as-deposited samples indicate that compressive stress acts in the a–b plane and tensile perpendicular to this. A schematic model of the structural and chemical changes in the as-deposited layers due to deposition inhomogeneity and low deposition temperature, based on the X-ray diffraction, energy dispersive X-ray, scanning electron microscopy and magnetic measurements has been developed.