Corrosion and Reciprocating Sliding Behavior of AC-HVAF Sprayed FeCrMoCBSi Amorphous Coating on Stainless Steel

To simultaneously protect the 304 stainless steel from corrosion and wear conditions, a FeCrMoCBSi coating with nearly full amorphous microstructure was deposited via activated combustion high-velocity air–fuel (AC-HVAF) technique. Initially, the porosity and microhardness of the coating were employed as two indicators to optimize the spray distance and powder feed rate. Then, the corrosion and reciprocating friction behavior of the best Fe-based amorphous (FA) coating and the bare 304 stainless steel were comparatively investigated. Experimental results show that the FA coating exhibited favorable corrosion resistance including high corrosion potential, low corrosion current density and additionally enhanced electrochemical impedance. Therefore, with FA coating deposited on the substrate, its surface was only subjected to slight etch pits instead of severe corrosion holes in a 3.5 wt.% NaCl solution. Besides, it is found that the sprayed FA coating could also effectively protect the substrate from severe abrasive wear and reduce its wear damage. The major wear mechanism was a combination of fatigue wear and adhesive wear derived from the micro-fracture and delamination at matrix and inter-splats.