| 摘要 |
PURPOSE:To inexpensively and easily produce a solar heat absorbing body having an excellent heat collecting characteristic by plating iron to the surface of a metallic base material essentially consisting of copper, then subjecting the surface to a chemical conversion treatment by an alkaline soln. to form a selective absorptive film on the surface. CONSTITUTION:The surface of the base material consisting of the metal essentially consisting of copper having excellent corrosion resistance or stainless steel is subjected to mirror finishing or finishing by cold rolling. The iron plating film of about 0.1-1mu film thickness is uniformly formed on the surface of such base material by using the iron plating liquid essentially consisting of, for example, ferrous sulfate. This base material is immersed the alkaline soln. to form the selective absorptive film consisting of the iron oxide essentially consisting of triiron tetraoxide or the composite of the iron oxide and the metallic element or oxide to constitute the alkaline soln. on the surface. A soln. mixture which is prepd. by using sodium hydroxide as an essential component and is added with an oxidizing agent such as sodium nitrite is preferable as the alkaline soln. The solar heat absorbing body having the selective absorptive film which is controlled in film thickness, has low emissivity, excellent heat resistance and heat collecting characteristic is thereby obtd.
|
