Predicting high temperature mechanical properties of CrN and CrAlN coatings from in-situ synchrotron radiation X-ray diffraction

•We investigated the phase composition of CrN and CrAlN coatings by in-situ high SR-XRD.•At the high temperature, a Cr2N phase was observed in the CrN coating.•SR-XRD measurements elucidate predictions of the crystallite size and strain of the main phases.•Observation showed that CrN is the major phase in Al and Cr coatings.

This contribution investigates the phase composition of CrN and CrAlN coatings by in-situ high temperature synchrotron radiation (SR-XRD), with the coatings deposited on steel substrate by closed field unbalance magnetron sputtering. Rietveld refinement on the SR-XRD spectra indicated CrN as the major phase, over the temperature range of 25 °C – 700 °C, for both coatings. At the high temperature of 700 °C, a Cr2N phase was observed in the CrN coating while the CrAlN coating also had a Cr phase. Williamson–Hall plots, from the refined data, afforded estimating variations of the strain and crystallite size of the major phase, up to 700 °C. The crystallite size (10 nm) for the CrAlN coating, at 25 °C, agrees very well with previous GI-XRD and TEM results obtained at room temperature Li et al. (2012).