| Abstrakt: |
This study investigates the effects of varied WC–Co/SiC high-velocity oxygen fuel (HVOF) coating compositions on the microstructural, mechanical, and wear properties of AISI 304 stainless steel. Microstructure evolution, phase composition, hardness distribution, and wear resistance were investigated using a series of coatings with increasing SiC content (from pure WC–Co to a WC–Co/SiC mix with 75% SiC). A gradual change from WC–Co-dominant microstructures in Sample A to SiC-rich structures in Sample E was observed by optical microscopy and scanning electron microscopy (SEM). This change was correlated with different surface morphologies and compositional features, confirmed by SEM–EDS analysis. Key phases with different intensities and peak broadening across samples were identified by X-ray diffraction (XRD), including WC, Co, SiC, and Fe₃C. Because of the harder SiC matrix, hardness profiles indicated that surface hardness increased with increasing SiC concentrations, peaking in Samples D and E. However, locally distributed brittleness was observed in coatings that were heavily SiC-dominated. While higher SiC content in Samples C through E resulted in slightly elevated wear rates, most likely due to increased brittleness, wear analysis showed that Sample B (WC–Co 75% & SiC 25%) had a decrease in wear rate, indicating an ideal composition for enhanced wear resistance. SEM examination of the worn surfaces revealed unique wear mechanisms, ranging from brittle fracture and microcracking in SiC-rich samples to plastic deformation in WC–Co-dominant samples. The study shows that while modest SiC additions to WC–Co coatings improve hardness and wear resistance in concert, too much SiC content may reduce durability because of brittleness. |
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