| 摘要 |
<p>A spectral selective absorbing surface on solar collector elements has a very high solar absorbing ability, in the range of 96% to 97% and a low thermal emittance, in the order of 10%, and can be produced with high capacity in industrial scale. A reactive gas in an amount of 1 to 50 cm 3/min kW, preferably 10 cm 3/min kW, distributed in the coating zone provides that the metal layer deposed onto the receiving material partly oxidizes during the deposition, whereby a layer is obtained that comprises a grain mixture of metallic material and metal oxide, whereby 40% to 80%, preferably about 50%, of metallic material is embedded into the metal oxide closest to the receiving material. The metallic material is successively decreased to about zero at the surface of the layer by increasing the addition of oxygen at the end of the coating zone. The metal is selected from the group consisting of nickel, chromium, cobalt, molybdenum, or the similar, or a mixture thereof, preferably a nickel-chromium-alloy where the ratio of chromium is 4 to 30%, preferably about 20%, and the grain size is <0.005 mm, preferably 0.001 mm.</p> |
