Characteristics and Failure Behaviors of an MnCo2O4 Spinel Coating in High-Temperature Oxidation Processes

A spinel MnCo2O4 coating was successfully prepared by depositing amorphous precursors on AISI430 substrates, which was sintered at 1000 °C for 3 h. The coatings showed excellent high-temperature oxidation resistance. The mass gain of the coated specimen was only ∼0.64 mg/cm2 when oxidized at 800 °C for 200 h, approximately 30% of the uncoated specimen. The failure behavior of the MnCo2O4 coating under thermal loading was calculated using a finite-element model established by the Voronoi principle. The results indicate that the stresses were first concentrated in the middle of the coating and near the interface. When cracks appeared to sprout and expand, the stresses were concentrated at the crack tips and released elsewhere near the cracks. The failure behaviors of the coating have been discussed in terms of the number of cracks and the energy consumption of crack damage.