The characteristics of a Pd-Ni/Pd-Cu double coating on 316L stainless steel and the corrosion resistance in stirred boiling acetic and formic acids mixture

A Pd-Ni/Pd-Cu double coating was deposited on stainless steel surface by electroplating. The microstructure and corrosion resistance of the double coating in strong reducing corrosive media were studied. In boiling 90 wt% acetic acid +10 wt% formic acid mixture containing 0.005 mol L−1 NaCl with 900 r min−1 stir, the corrosion rate of the double coating coated 316L stainless steel is one order of magnitude lower than that of Pd-Cu coated samples. The double coating shows lower porosity, higher hardness and elasticity modulus as well as higher adhesive strength, which may explain the better corrosion resistance in the testing environments.