| Cr-Pd alloy films with good corrosion resistance, high hardness has been recently developed as a kind of new and protective membrane, To optimize the electroplating process, conductive salt and additive of the bath were studied. Based on the single factors study, the optimal composition formula was obtained by an orthogonal method. And with the optimal formula, the influence of bath composition and operating conditions on the properties of solution and coatings was studied.An uniform chromium-palladium film on 316 stainless steel was obtained by electroless plating. Scanning electronic microscopy, x-ray photoelectron spectroscopy, weight loss tests and electrochemical measurements were used to character the properties of the film. Corrosion behaviors of the chromium-palladium plated samples in acetic and formic acid mixtures at boiling temperature and the 20% sulfuric acid were studied. Finally, the reasons of the chromium Palladium alloy films enhance the corrosion resistance of 316L stainless steelwere discussed. The electroplated films were mainly composed of chromium and palladium. In the Cr-Pd films both Cr and Pd presented mainly in metallic state, with the grain sizes less than 100 nm. The Cr-Pd plated sample showed higher microhardness than Pd plated sample and 316L stainless steel. On the surface, Cr(OH)3 and Cr2O3 were present. The crystallite size decreased with the increase of Pd content in the Cr-Pd alloy films. The adhesive strength was examined by cross-cut tape test, thermal shock test and Cross-cut tape test, and the adhesion of the film to stainless steel was quite good.In boiling 20% H2SO4 solution, corrosion rates of the Cr-Pd plated samples were about four orders of magnitude lower than that of the original 316L stainless steel samples. With the increase of chromium content in the Cr-Pd films, corrosion potential of the Cr-Pd plated stainless steel samples decreased, but the impedance of the film increased.
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