The electroplated palladium–copper alloy film on 316L stainless steel and its corrosion resistance in mixture of acetic and formic acids

Palladium–copper alloy films (Cu 2.93–5.66 at.%) were deposited on 316L stainless steel by electroplating. The films showed good adhesive strength and increased surface micro-hardness. In boiling mixture of 90% acetic acid + 10% formic acid + 400 ppm Br− under stirring (625 r/min), the Pd–Cu films showed better corrosion resistance than Pd film. The Pd–5.66%Cu films showed the lowest corrosion rate almost three orders of magnitude lower than that of 316L matrix. The increased corrosion resistance of Pd–Cu films was attributed to the improved passivity, better barrier effect, increased surface hardness and the effect of Cu to resist pitting.