Electrodeposition of Co-Mn3O4 composite coatings

Electrolytic codeposition was employed as a low-cost alternative process to fabricate composite coatings containing Mn3O4 particles in a Co matrix for potential applications in solid oxide fuel cells. The effects of codeposition parameters on the Mn3O4 particle incorporation, cathode current efficiency, and coating uniformity were investigated using a Design of Experiments (DoE) approach. Concentration of Mn3O4 particles in the plating solution, agitation rate, current density, and solution pH were the four factors considered in the fractional factorial 2(4-1) design. With different combinations of the deposition parameters, the amount of Mn3O4 particles incorporated in the composite coatings ranged from 0 to 12 vol.%. The DoE results indicate that the pH of the plating solution exhibited the greatest importance on both particle incorporation and current efficiency, which were decreased significantly below pH 2. The Mn3O4 concentration in the plating bath showed the second strongest effect on particle incorporation, followed by the agitation rate. While the applied current density did not appear to affect the Mn3O4 particle incorporation, it had a strong influence on coating thickness uniformity.