Comparative Investigation on the Impact Abrasive Wear Behavior of PTAW NiBSi Coatings Reinforced With Different Types of Tungsten Carbide

NiBSi‐based coatings reinforced with spherical cast tungsten carbide (NSC coating), irregular cast tungsten carbide (NC coating), and macrocrystalline tungsten carbide (NMC coating) are investigated to elucidate the impact of abrasive wear behavior. The influence of dissolution and reprecipitation behaviors of various tungsten carbides on the microstructure of the coating is analyzed. The spherical and irregular cast tungsten carbide with eutectoid WC + W 2 C lamellar structure was partially decomposed, leading to the formation of WC + W 2 C eutectoids with partial transformation to M 4 (C, B) and granular WC at the exterior of remaining particles. Blocky M 4 (C, B) and reticular M 6 (C, B) were observed in the NSC and NC coatings. Reprecipitation of WC occurs at the surface of macrocrystalline tungsten carbide, and M 6 (C, B) reticular structure forms in the NMC coating. The NSC coating exhibits the lowest wear rate and the best wear resistance under all impact abrasive wear tests. The wear resistance was approximately 2.55 times at 1 J, 2.32 times at 3 J, and 2.38 times at 5 J impact energy relative to the NMC coating. The NC coating exhibited improved wear resistance of about 1.63 times at 1 J, 1.41 times at 3 J, and 1.36 times at 5 J impact energies compared to the NMC coating. Although secondary carbides increase the hardness of the matrix for the NSC and NC coatings, their fracture under impact degrades the wear performance. The finest WC + W 2 C eutectoids in the tungsten carbide particles with the highest hardness and toughness increase crack path tortuosity and energy dissipation, resulting in the best wear performance of the NSC coating.