Microstructure and high temperature tribological br br

High-entropy alloy coatings show great potential for improving the wear resistance of the stainless steel substrate. To investigate the effects of Cu/Si doping on the microstructure and high temperature tribological properties of FeCoCrNi high-entropy alloy coating, FeCoCrNiCu, and FeCoCrNiSi, series of high-entropy alloy coatings were prepared on the 304 stainless steel by laser cladding. The microstructure and phase distribution of the coatings were characterized by XRD, SEM and EDS, and the high temperature tribological properties of the coatings were tested by a high temperature friction and wear tester. The results show that both FeCoCrNiCu, and FeCoCrNiSi, high entropy alloy coatings form a single FCC-type solid solution with good metallurgical bonding to the substrate under suitable laser cladding parameters. The addition of Cu reduces the surface hardness of FeCoCrNi coatings, but improves the metallurgical bonding due to the increase of thermal conductivity of the coating; the addition of Si promotes grain refinement and improves the surface hardness of the coating. At 600 C, the addition of Cu/Si elements significantly improves the tribological properties of the pating, with the coefficients of friction of 0. 24 and 0. 19 for FeCoCrNiCu and FeCoCrNiSi coatings, respectively, and the wear rates are 1. 58 X 10 mm(2) Nm and 6. 77 X 10 mm(2) Nm"(2), respectively, which are 56. 1% and 81.9% lower than FeCoCrNi coating. The main wear mechanisms of FeCoCrNiCu coating are oxidation wear, fatigue wear and slightly abrasive wear, while FeCoCrNiSi coating is oxidation wear.