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An eletrolyte is proposed for the deposition of black cobalt selective absorber coating on copper plate. The influence of the electrolyte composition and operating parameters on the properties of black cobalt coatings including optical properties were studied. The optimum conditions to obtain a high absorptance/emittance ratio are described.

Solar thermal collectors represent a widely used type of system for the conversion of solar energy. In order to produce selective coatings on aluminium substrates to be used as absorber plates in high efficiency solar collectors, nickel pigmentation was applied to anodically oxidised surfaces. Electrochemical dc methods are used to study the oxidation of aluminium as functions of the following electrolysis conditions: applied current, pH, temperature and concentration of electrolyte. The properties of the oxidised aluminium surfaces are investigated by cyclic voltammetry. Nickel pigmentation of porous aluminium surfaces was also performed as a function of electrochemical pigmentation conditions by ac electrodeposition. Mechanisms contributing to selectivity in anodically oxided aluminium and electrodeposits are discussed. The optical properties of the prepared surfaces are optimised, and solar absorptance as=0.91 and thermal emittance et,23°C=0.17 are obtained.

Films of CdS for photovoltaic devices were electrochemically deposited on tin oxide coated glass substrates at different conditions. The films were found to be smooth and uniform with a small grain size. X-ray diffraction measurement and analysis indicated a hexagonal phase rather than the cubic phase. The surface composition of the films was investigated by Auger Spectroscopy. Electrochemical deposition parameters were studied to obtain the optimum conditions for the best CdS films. Our films are compared from the pinhole number and particulate point of view with the films prepared by other methods.