A study of sol gel process parameters on CoCuMnOx selective coating characteristics

This research addresses the effect of process parameters on the optical properties of solar selective coating. The proposed study discusses the deposition of a selective coating of CoCuMnOx onto stainless-steel substrate. The coating was prepared via a sol-gel route and dip coating process. Mechanical adhesion between the coating and the substrate was increased through increasing the surface roughness of the substrate. Four parameters were discussed; precursor concentration, withdrawal rate, number of coating layers and the heat treatment temperature. The best achieved absorptivity was 0.906 in the wavelength range of (200-900 nm) and emissivity was 0.116 in the wavelength range of (2.5-25 mu m) for a sample with precursor molar ratio divided by 60, 1.5 cm min(-1) withdrawal rate, double coating layer and 450 degrees C heat treatment temperature. Detailed coating characterization was discussed through XRD, EDX and SEM analysis.