PREPARATION OF NEW BLACK CHROME SOLAR SELECTIVE COATINGS

The application of the pulse current electrolysis method for black chr ome oxide electrocrystallization on nickel substrate, named KIEROME, h as been investigated. Pulse plating parameters to optimize the optical properties of KIEROME included the bath composition, current density, plating time, and duty cycle. The bath composition was prepared with the formula of 250-300 g/l chromic acid, 10-15 g/l propionic acid and 0.5 g/l of a proprietary additive. It has been observed that the KIERO ME exhibited reasonable optical properties for commercialization when the plating parameters were properly controlled: absorptance (alpha) o f 0.944, and emittance (epsilon) of 0.084. Thermal aging tests associa ted with the changes in optical properties, surface microstructures an d composition profiles were also performed by aging at 300 degrees C a nd 450 degrees C in air for 24 hours. The surface microstructures of t he as-deposited and thermally treated KIEROME coatings were investigat ed using Scanning Electron Microscopy (SEM), Auger Electron Scopy (AES ) and X-ray Photoelectron Spectroscopy (XPS). This study implies that the KIEROME exhibits good optical properties and reasonable thermal st ability for the practical application.