Effect of process parameters on properties of Mn1.5CuFe0.5O4 spinel oxide coatings deposited by spray pyrolysis method

One of the critical issues in the lifetime of metallic interconnects is related to their high oxidation rate and Cr diffusion, which negatively affect their performance. In the present study, a novel Fe modified Mn–Cu spinel oxide with the chemical composition of Mn 1.5 CuFe 0.5 O 4 as protective coating was deposited on the surface of Crofer 22 APU and alumina by the spray pyrolysis method. The effects of different deposition conditions including deposition temperature, spraying speed, and volume of precursor on the properties of deposited spinel coatings were investigated. Scanning electron microscopy characterizations showed that the deposited layer was uniform and non-cracked at the deposition temperature of 400 °C. However, at temperatures of 300 °C and lower, the deposited layers became non-uniform and cracked. Additionally, spraying with speeds of 10 ml/h and lower resulted in uniform and non-cracked coatings, and a higher spraying speed of 15 ml/h caused a nonuniform and cracked layer. Atomic force microscopy measurements proposed that the value of R a was reduced by increasing the deposition temperature and reducing the spraying speed. X-ray diffraction characterization showed that deposition temperature has affected the phase structure of deposited spinel oxides on both substrates. According to electrical conductivity measurements, deposited layers at higher deposition temperatures with lower spraying speeds showed higher electrical conductivity and lower activation energy. Decreasing the deposition temperature reduced the electrical conductivity of the spinel oxide coatings. • Mn 1.5 CuFe 0.5 O 4 spinel oxide was deposited using spray pyrolysis method and assessed as a potential coating material. • Uniform and crack-free coatings were applied to Crofer 22 APU and alumina. • The coating thickness for 100 ml of precursor onto Crofer 22 APU and alumina was 7.19 and 7.55 μm, respectively. • Deposition temperature was the most critical factor in the properties of the spinel oxide coating. • The deposited coating at 400 °C with low spraying speed exhibited the highest electrical conductivity.