Microstructure and High-Temperature Electrochemical Corrosion Resistance of Magnetron Sputtered Cr-C Coating on 304 Stainless Steel Surface

The Cr-C coating was deposited on the surface of 304 stainless steel current collector by magnetron sputtering technique. The microstructure, the phase composition and the electrochemical corrosion resistance in the molten sodium polysulfide at 350℃ of the coating were studied. The results show that the prepared Cr-C coating was uniform and dense, and was composed of Cr₃C₂, Cr₇C₃ and Cr phases. After corrosion in the molten sodium polysulfide for 120 h, the phases of Cr₃C₂、Cr₇C₃, NaCrS₂ and Cr₂S₃ were formed on surface of the Cr-C coating. The Cr-C coating resistance increased with corrosion time and reached 1 454 Ω·cm² after corrosion for 120 h, indicating that the coating could effectively inhibit the diffusion of the molten sodium polysulfide to the surface of the 304 stainless steel substrate, thereby preventing the substrate from high temperature molten-salt corrosion effectively.