Ni-Al2O3 cermet films were sputtered from a hot pressed Ni-Al2O3 composite target, in a RF planar magnetron sputtering system. Coatings of various thickness were deposited on different substrates and their absorptance (α) and emittance (ε) were obtained in the solar and thermal infrared regions, respectively, to evaluate their use as spectrally selective surfaces. Films were also deposited on different substrates with SiO2 anti-reflection coatings and an α of 0.88 to 0.92 and ε of 0.07 to 0.33 were obtained. Films of about 700 Å thick deposited on molybdenum-coated nickel-plated stainless steel substrates with 600 Å SiO2 AR coating and annealed at 550°C in air for six hours have best selective properties with α=0.91 and ε=0.07. These coatings are stable up to 500°C in air for more than 1000 h. ESCA and Auger depth profilings were done to estimate the composition and its variation with depth.
|Number of pages||14|
|Journal||Solar Energy Materials|
|Publication status||Published - 1989|