Infrared reflectance of direct current magnetron sputter deposited films of Ni93V7, Cu89Ni10Fe1(Mn) and Cu

Direct current magnetron sputter deposition of thin metal films from nickel- and copper-based alloys have been used to prepare infrared reflectors in spectrally selective solar absorbers. The sputtering process was optimized regarding sputter rate, argon pressure and base pressure in order to achieve maximum infrared reflectance for each target material. The structural properties of the films were investigated by scanning electron microscopy and X-ray diffraction. It was found that the near normal thermal emittance at a surface temperature of approximately 100 degreesC can be reduced from 0.12 to 0.06 if nickel-chromium, which is commonly used as infrared reflector in tandem solar absorbers, is substituted by copper-nickel. (C) 2002 Elsevier Science B.V. All rights reserved.