Influence of some electrodeposition parameters on formation of nanostructure black cobalt coating used for solar energy absorption

Abstract EN

Electrodeposition of nano cobalt on a stainless steel 304 substrate used for solar energy absorption was established.

Two different electrolytic bathes were used in this investigation.

The first bath composition was [270 g/l CoSO4, 35 g/l CoCl2, 2.5 g/l Co(NO3)2 and 30 g/l H3BO3], and the second was as the previous without addition of Co(NO3)2.

The role of nitrate ions as an oxidizing agent was investigated.

Different current densities (20 and 30 mA/cm2) were applied.

The optimum time of deposition was found to be 6 minutes for each used current density.

Crystal structure transformation and morphology changes were investigated for coatings at all electrodeposition conditions.

SEM and EDAX were used for monitoring the gradual changes in the coated surface and nanostructure formation behavior.

The degree of crystallinity and crystallite size changes were measured using XRD.

The optical properties such as absorption and reflectivity were investigated using UV-IR Spectrometry to find and compromise the effect of applied electrodeposition conditions on the solar energy absorption of the formed surface coating.

The absorptance had values up to 98% for the high energy region of sunlight spectrum at electrodeposition conditions of the first bath when using cobalt nitrate.