Chromium–palladium films on 316L stainless steel by pulse electrodeposition and their corrosion resistance in hot sulfuric acid solutions

Chromium–palladium alloy films with good adhesive strength and higher micro-hardness have been deposited on 316L stainless steel by pulse electroplating. The films are composed mainly of chromium and palladium crystallites in the metallic state, with grain sizes less than 100 nm. On the film surface Cr(OH)3 and Cr2O3 are present. The co-deposited Cr and Pd in the films show a synergetic effect on passivation. In boiling 20 wt.% H2SO4 solution, boiling acetic–formic acid mixture, and simulated PEM fuel cells environment, the Cr–Pd-plated 316L steel shows excellent corrosion resistance.

► Cr–Pd alloy films have been deposited on 316L stainless steel by pulse electroplating.
► By adjusting Pd2+ content in plating solution, Cr/Pd ratio of the film may be changed in a wide range.
► The Cr–Pd film significantly promotes passivation of stainless steel in non-oxidizing mediums.
► In boiling 20 wt.% H2SO4 solution, corrosion rate of Cr–Pd plated SS reduces by four orders of magnitude.
► Just 2.7 wt.% Pd in Cr–Pd film significantly improved passivity of 316L SS in boiling H2SO4 solution.