OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 4 2023 Fig. 3. Microhardness of coatings The microhardness of Fe31W10Cr22Mo7B12C18 coatings was in the range of 6.65–7.56 GPa (fig. 3), which is 2.3–2.6 times higher than that of uncoated Steel 35, and also exceeds the values obtained by other researchers for MG Fe47Cr20Mo10W6C15B6Y2 (1.28 GPa) [27], is commensurate with the values for MG Zr50Cu28Al14Ni8 (7.2 GPa); Cu48Zr42Al6Ti4 (4.0 GPa); Hf46Cu45Al6Ti3 (7.7 GPa) [28], inferior to the data obtained for MG Fe65Ti13Co8Ni7B6Nb1 (11.6 GPa) [27] and MG Fe41Cr8Ni8Mo8Co8C16B11 (10–15 GPa) [29]. The friction coefficient values of the studied coated specimens monotonically decreased from 0.49 to 0.44 with increasing pulse on-off time from 50 to 450 (fig. 4, a). The friction coefficient of the coated specimens was smaller than that of uncoated Steel 35 (0.6) and was commensurate with the previously obtained data for Zr35Ti30Cu8.25Be26.75, (0.43–0.6) [11], slightly inferior to the data obtained for Zr56.2Ti13.8Nb5.0Cu6.9Ni5.6Be12.5 (0.27–0.35) [30]. However, the latter MGs contain beryllium, which is extremely toxic. The present relative values of wear rate of specimens with coatings was in the range from 0.86×10-5 to 1.45×10-5 mm3/(Nm) (fig. 4, b). Thus, the use of Fe 31W10Cr22Mo7B12C18 metallic glass coatings can increase the wear resistance of the surface of Steel 35 by 2.0–3.3 times. The lowest values of wear rate were shown by the coating obtained at the lowest pulse on-off time of 50. The high-temperature resistance test of specimens characterizes not only the resistance of the coating material to oxidation, but also the continuity of the deposited layer. The mass change kinetics of specimens with Fe31W10Cr22Mo7B12C18 coatings (fig. 5, a, left scale) and uncoated Steel 35 (fig. 5, a; right scale) at temperature 700 °C is shown. The weight gain of the specimens is due to the fixation of oxygen on its Ta b l e 3 Characteristics of the deposited coatings Parameter Steel 35 МС50 МС150 МС450 Coating thickness ha.th, μm 80.6 77.1 56.1 Roughness Ra, µm 3.2 ±1.5 6.79±1.54 7.34±1.74 5.46±0.92 Wetting angle, °(degree) 57.5±3.8 111.9±6.1 108.4±7.3 121.3±4.9 Surface energy 39.97±17.6 32.3±18.7 33.1±17 29.9±15.5 a b Fig. 4. Coefficient of friction (a) and wear (b) of coatings compared to Steel 35 at a load of 25 N
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