NiCrBSi alloys are a group of nickel-based alloys and are used in cases where resistance to wear, erosion and corrosion is required in the system at the same time. This coating is available at a relatively low cost. In this research, the wear, erosion and corrosion properties of Colmonoy 4, Colmonoy 5 and Colmonoy 6 coatings coated on 420 stainless steel substrate by plasma transferred arc welding (PTAW) process have been investigated. The microstructural and phase investigations of the coatings were carried out using X-ray diffraction (XRD), optical microscope (OM) and scanning electron microscope (SEM), equipped with an energy dispersive spectrometer. The results showed that the microstructure of stainless steel 420 is martensitic structure and chromium carbides in the intergranular spaces and grain boundaries in the martensitic field. Considering that the initial composition of all three coatings has a high percentage of nickel, the coating is mainly composed of γ-(Ni-Fe) phase. In addition, by analyzing the X-ray diffraction patterns of the coatings, it was determined that Ni3B, Cr2B, Cr7C3, and Cr3C2 phases exist in Colmonoy 4, Colmonoy 5, and Colmonoy6 coatings, which according to the different percentage of alloying elements in each alloy, the abundance of phases in each of these coatings is different. Is. The resistance to wear, erosion and corrosion of the coatings and the substrate was eva‎luated. Tribological studies showed that Colmonoy coatings have better wear and erosion resistance than the substrate. By increasing the amount of chromium, carbon and boron in the coatings, the formation of hard carbide and boride phases increases in the nickel field and improves the hardness and wear properties. Among the samples, Colmonoy 6 coating showed the best wear behavior due to the presence of the most carbide and boride hard phases. The dominant wear mechanisms in the coatings were adhesive and abrasive wear, but for 420 stainless steel, sheet wear mechanisms were observed. According to the results of the erosion test, Colmonoy 6 sample at 30 degree angle due to higher hardness and Colmonoy 4 sample at 90 degree angle due to greater toughness had better erosion performance. By examining the results of corrosion, it was found that stainless steel 420 has more resistance to corrosion, due to the formation of a passive film on it. Due to the formation of cracks during the coating operation, Colmonoy coatings showed less corrosion resistance than the substrate.

عبدالمجيد اسلامي , فخرالدين اشرفي زاده

مهران نحوي , حميدرضا سليمي جزي