OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 3 2025 a b Fig. 7. Coefficient of friction at a sliding speed of 0.47 m/s and wear rate of coatings at 0.47 and 1.89 m/s original Steel 45. At a sliding speed of 0.47 m/s, the wear of the samples was higher than at a higher speed (1.89 m/s). This can be attributed to the formation of a self-lubricating tribo-oxide layer, resulting from the high instantaneous temperature reached in the friction zone at the higher sliding speed [23, 24]. At both speeds, the WCn coating exhibited the lowest wear resistance, while the WC40 coating exhibited the highest. The high wear resistance of the WC40 coating can be attributed to the presence of large WC inclusions and areas with their accumulation, which prevented the counterbody from interacting with the abraded metal matrix of the coating. Based on the weight gain plots of WC/Fe-Ni-Al coatings and Steel 45 at 700 °C, after 100 hours of testing, the weight gain of coated samples ranged from 37.0 to 133.8 g/m2, while that of uncoated Steel 45 was 429.2 g/m2 (Fig. 8, a). The weight gain of the coated samples increased with increasing powder dispersion, increasing by 2.6 times when transitioning from the WC20 sample to the WCn sample. Thus, the results indicate that decreasing the diameter of tungsten carbide particles reduces the oxidation resistance of the WC/Fe-Ni-Al composition. This may be due to the increased decarburization of WC particles with an increase in their specific surface area, leading to a greater introduction of W and C elements into the a b Fig. 8. Graphs of weight gain of WC/Fe-Ni-Al coatings and 45 steel over time at a temperature of 700 °C (a) and XRD patterns of coatings after oxidation resistance testing (b)
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