OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 2 2023 Figure 7 shows the plot of the dependence of FWHM of (111) CrN and (111) ZrN phase reflections on the temperature. Based on the possibility of the occurrence of microstresses with an increase in the FWHM value, it can be concluded that microstresses can occur to a small extent for the CrN phase of the multilayer coating up to 200 °C. After reaching the temperature of 200 °C, the FWHM value remains, on average, at the same level. For the ZrN coating component, the FWHM value slightly increases up to the temperature of 400 °C, and then the FWHM value decreases, accordingly, microstresses will also have a decreasing dependence. As a result of the sequential actions with obtaining X-ray diffraction patterns of samples with coatings under temperature exposure, sampling and evaluation of X-ray diffraction patterns according to the proposed algorithm, recommendations for the application of coating technologies depending on the parameters of coating application can be made. The recommendations consist of a two-stage algorithm, consisting of: 1. Determining the CLTE of individual coating components; 2. Determining the FWHM and comparing it with the FWHM minimum of two samples with coatings. If the calculated CLTE values for some coating components exhibit differences, the deposition mode in which the CLTE of coating components exhibits the minimum differences at any temperature is selected as the optimal deposition mode. The temperature, at which the CLTE of coating components exhibits the minimum differences or is equal, is selected as the optimal mode of multilayer deposition, and the coating in which the FWHM values, as determined by the X-ray profile approximation, exhibit a decreasing dependency, is most suitable for prolonged use due to the minimal microstresses existing in the coating. Conclusions Based on the conducted research using the proposed algorithm, conclusions and recommendations can be made regarding the application and use of CrN/ZrN coatings: A multilayer coating of CrN/ZrN deposited at a table rotation speed of 0.5 revolutions per minute (rpm) had varying CLTE values throughout the entire thermal testing, with differences in CLTE between components exceeding 50%. For the multilayer coating deposited at a table rotation speed of 8 rpm, the CLTE dependence was found to be linear only for the CrN component, while the ZrN component exhibited an extremum in the temperature range of 400 °C. Prior to heating the coating to 400 °C, the CLTE was negative, and after reaching 400 °C, it changed sign to positive. This indicates that within a narrow temperature range around 400 °C, the CLTE of both coating components will not differ significantly. Therefore, the coating application mode with a table rotation speed of 8 rpm will be optimal. Based on the FWHM data, the occurrence of microstresses is possible for both coating application modes (0.5 and 8 rpm). However, for the coating application mode with a table rotation speed of 8 rpm, no microstresses were observed for the CrN component, even after exposure to 500 °C. This leads to the conclusion that this deposition mode for the multilayer coating is optimal. Fig. 7. Dependence of FWHM reflection of (111) CrN and (111) ZrN multilayer coating on temperature References 1. Liu J., Hao Z., Cui Z., Ma D., Lu J., Cui Y., Li C., Liu W., Xie S., Hu P., Huang P., Bai G., Yun D. Oxidation behavior, thermal stability, and the coating/substrate interface evolution of CrN-coated Zircaloy under hightemperature steam. Corrosion Science, 2021, vol. 185, p. 109416. DOI: 10.1016/j.corsci.2021.109416. 2. Pashkov D.M., Belyak O.A., Guda A.A., Kolesnikov V.I. Reverse engineering of mechanical and tribological properties of coatings: results of machine learning algorithms. Physical Mesomechanics, 2022, vol. 25, pp. 296–305. DOI: 10.1134/S1029959922040038.
RkJQdWJsaXNoZXIy MTk0ODM1