In-situ analysis of ZrN/CrN multilayer coatings under heating

Abstract

Introduction. Advanced hard coatings combine different properties such as high hardness, wear resistance, corrosive resistance. At present, layer-by-layer deposited zirconium and chromium nitrides are promising hard coating materials. Currently, the multilayer coating process is not sufficiently described in the literature to understand all the processes involved. The problem is the complexity of depositing thick layers of multilayer, multicomponent coatings with different physical characteristics of the coating components. First and foremost this concerns the coefficient of linear thermal expansion (CTE). Since the coating and operating processes consist in heating, coating components with different CTE will be susceptible to cracking, further failure and product failure over time. The purpose of work is in-situ study of multilayer ZrN/CrN coatings by X-ray analysis using synchrotron radiation and qualitative microstress behavior of multilayer coatings formed by plasma-assisted vacuum-arc method on substrate of alloy VK8 (92% WC–8% Co) under heating up to 750°С. Research methodology. Samples of coatings made of chromium and zirconium nitrides deposited on a substrate of the hard alloy VK8 are investigated. The basic method is the X-ray analysis using synchrotron radiation. We used the most common techniques to study the characteristics of multilayered coatings such as the coefficient of linear thermal expansion and the qualitative measurement of microstresses. Results and discussion. The result is the ability to determine changes in the characteristics of multilayer coatings during heating, such as changes in the crystal lattice parameter of each of the coating components separately, the possibility to determine the coefficient of linear thermal expansion of the coating components and the qualitative measurement of microstresses, as well as providing the opportunity, based on the analysis, to form recommendations for further application of the technology of applying multilayer coatings with given characteristics.