<title>Cobalt-cadmium solar selective black coating</title>

Abstract

This paper describes the development of electro-deposited selective cobalt-cadmium coating for solar thermal energy conversion. Electrolyte composition and operating conditions were standardized by the use of Hull Cell. Ammonium thiocyanate has been used as a complexing agent to produce quality black coating with good optical properties. Cetyl trimethyl ammonium bromide (CTAB) has been used as an addition agent to improve the physical properties of the deposit. The present system has been studied in the current density range 1.6 to 8 A/dm<SUP>2</SUP>. Solar absorptance ((alpha) ) of 0.94 and thermal emittance ((epsilon) ) of 0.1 were achieved. A thermal cycling test was also carried out. It showed decrease in the thermal emittance ((epsilon) ) and increase in the solar absorptance ((alpha) ) and thereby shows its ability for use in high temperature solar thermal energy conversion systems.