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AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorGlen E. McDonald
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This invention is concerned with an improved plating process for covering a substrate with a black metal oxide film. The invention is particularly directed to making a heating panel for a solar collector. A compound is electrodeposited from an aqueous solution containing cobalt metal salts onto a metal substrate. This compound is converted during plating into a black, highly absorbing oxide coating which contains hydrated oxides. This is achieved by the inclusion of an oxidizing agent in the plating bath. The inclusion of an oxidizing agent in the plating bath is contrary to standard electroplating practice. The hydrated oxides are converted to oxides by treatment in a hot bath, such as boiling water. An oxidizing agent may be added to the hot liquid treating bath.
In a method of covering a substrate with a black metal oxide film from an electroplating bath containing about 270 grams per liter of cobalt sulfate, about 37 grams per liter of cobalt chloride, and about 30 grams per liter of boric acid having a pH in the range between about 1.5 and about 4.5 at a temperature between about 45.degree. C. and about 60.degree. C. to form a coating that is highly absorbing, the improvement comprising the steps of
Dependencies are inferred from the claim text.