Corrosion Studies on Graphite Encapsulated FeCo Nanoparticles Modified Black Chrome (MBC) Spectrally Selective Coatings

Black chrome (BC) and graphite encapsulated FeCo nanoparticles modified black chrome (MBC) composite thin films were prepared on stainless steel substrates using electrodeposition technique under galvanostatic condition. Three different weight proportions of GE FeCo NPs, 0.025, 0.05, and 0.1 wt% in 200mL in black chrome electrolyte bath solutions were used for MBC thin film synthesis. A saline environment of 3.5% NaCl solution was used to carry out cyclic voltammetric and Tafel studies to understand the impact of corrosion on BC and MBC solar selective coatings. We carried out structural, microsctrucural, optical, vibrational and mechanical studies on these pristine (BC & MBC) and saline environment treated solar selective coatings. We observed that roughness and grain size of MBC solar selective surfaces decrease with increase in weight % of graphite encapsulated FeCo NPs during corrosion. More interestingly, after Tafel measurements, mechanical studies on MBC coatings showed enhanced hardness and Young’s modulus with respect to pristine BC coatings.

Keywords: Electrodeposition; Black Chrome; Graphite encapsulated FeCo NPs, Solar selective coatings