| 摘要 |
This invention relates to a selective absorption surface of a solar collector in which a coating layer consisting of the predetermined composition of metal oxide is tightly adhered to a substrate having the mirror-like surface in the predetermined thickness. The composition of metal oxide consists of 0.001-0.15 % C, 0.005-3.00 % Si, 0.005-10.0 % Mn, 11.0-30% Cr, 0.005-22.0 % Ni, optionally 0.75-5.00 % Mo and the balance being Fe. The metal plate is chemically oxidized in an acidic bath consisting of 150-800 g/l of sulfuric acid at the temp. of 50 ≦̸C to the boiling point, a dipping time of 3-40 min. to form the oxide film at the thickness of 500 to 200∦.
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