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

•The films deposited at 450 °C both contained the MAX phase and solid solution.•The films were polycrystalline with (110) texture, and columnar growth.•Film stress was compressive in the a–b plane and tensile perpendicular to this.•No difference was found in this result upon the introduction of up to 0.3 at.% Y.•Introduction of a film structure model based on XRD, EDX, SEM and magnetic results

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 (0.1–0.3 at.%), 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 0.1–0.3 at.% 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.