A study of performance of black chromium coating materials for solar thermal energy application

Black chromium coating has becomes an important process for metal finishes especially in solar energy utilisation. It has many applications in various fields; such as for non-reflecting coatings, decorative coatings and solar selective coatings [1]. This work is focused at solar selective coatings where it is used for thermal energy application. The coating surface that absorbs solar energy should have an ideal solar selective surface such as high absorption (a) in solar spectrum near infrared region (IR) [2]. Electroplating is used as a technique to produce a black coating finishes. It is a simple room temperature test, which is cost effective for modification of surfaces. The black chromium coating finishes is determined by using hull cell rest where the current range from 1-10 Amp, with 10 minutes plating time is estimated to simulate the actual plating process. Through the hull cell test process, results has shown that the black chromium coating can be obtained at temperature 24-33degreesC, with current densities range from 5-30 A/dm(2). Two different current density (25 and 30 A/dm(2)) is used to produce optimum black colour as determined from hull cell test. With plating time 4 to,10 minutes act as measured parameters, the absorption rate of 0.86-0.97 are obtained. The present black coating produced, showed a powdery deep black colour, with adherent film upon a conductive base, has a great potential for solar thermal energy applications.