Electrodeposition of hexavalent-Chromium free black coatings for flat high temperature solar thermal collector-Master Thesis VLADA PASTUSHENKO

Author: VLADA PASTUSHENKO ; Type of thesis: Master Thesis
Abstract: A solar collector is an apparatus that collects the sunlight energy, and then alters this energy into a more usable or storable energy form. The absorber surface used in thermal solar collectors requires high absorptance in the solar spectrum and low emittance. Several techniques, such as vacuum techniques, are currently used to produce solar absorber surfaces. However, the desired characteristics of the solar absorber coating may be better controlled by direct electrodeposition. Other electrodeposition advantages are basically rapidity, low cost, free from porosity and industrial applicability. Copper substrate was chosen due to its use in a large variety of domestic and industrial piping as a thermal and electrical conductor. Black chromium is an important coating material used in solar thermal systems as a spectrally selective surface. This coating is usually obtained by electrodeposition from sulphate free chromium (VI) aqueous solutions which represent a health and environmental hazard due to the presence of Cr (VI), a known toxic and carcinogenic agent. Recent developments in green chemistry have shown that ionic liquids can be used as electrolytes, allowing the deposition of a wide range of materials with negligible environmental and health impacts.