(Co,Mn)₃O₄ Spinel Coating for Protecting Metallic Interconnects Thermally Converted from an Electro‐Codeposited Co‐Mn₃O₄ Composite Coating

Abstract

Electro-codeposition was used to prepare the Co and Co-Mn3O4 precursor coatings on ferritic stainless steel E-brite. Plated samples were exposed at 800°C in air for different durations (i.e., 10 min and 4 h) for thermal conversion of the deposited layer to a spinel coating. The converted layer was characterized with scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). The results showed that after 10 min heat treatment, the plated Co layer was not fully oxidized and converted into a double-layer microstructure with an inner CoO layer and outer Co3O4 layer, while for the Co-Mn3O4 layer, the Mn3O4 particles were not completely dissolved into the oxide layer. After 4 h of exposure, the surface layer was fully converted into the Co3O4 or (Co,Mn)3O4 spinel coating. Though the Mn content in (Co,Mn)3O4 was relatively low, the Mn-doped spinel coating was advantageous over the pure cobalt spinel coating, as the thermally grown Cr2O3 scale at the coating/substrate interface was more compact and protective. Co diffusion from the deposited layer into the alloy substrate was observed for both coatings.

Effect of Current Density on Deposition of Ni-Mn3O4 Composite Coating and its High Temperature Behavior

“…13 Thus, it is suitable as a potential coating material for the steel interconnects. Although co-depositing oxide particles into metal matrix followed by subsequent thermal oxidation to form spinel layers directly on the steel has been currently considered as a simple technique, 14,15 it is difficult to realize the deposition of coating with high content of particles. Methods to improve the particle content in composite coatings have attracted much attention since the content of particles directly impacts the amount of formed spinel.…”