| 摘要 |
PURPOSE:To permit to increase absorption coefficient under maintaining good radiation coefficient by remaining cavities on the upper part of fine holes in a porous anodized film produced on the surface of base material of aluminum. CONSTITUTION:Known radiation coefficient can be suppressed to a sufficiently low value by forming the selective absorption film of 0.4-1.0mum on the surface of an aluminum member. Further, the tinting of the surface of the film is improved, the refractive index of the surface layer thereof is reduced to a small value, the surface reflection of light of incidence is reduced and a good absorbing characteristic for the solar heat energy is shown in spite of the separating amount of metal of small amount by a method wherein the fine holes of the anodized film are filled with the separated metal within the range of 20-80% of the thickness of the film and the cavities are remaining substantially in the upper parts of the fine holes. Accordingly, the selective absorption film for the solar heat energy, which is provided with a prominent performance in the selective absorption characteristics evaluated by the relative relation between the absorption coefficient and the radiation coefficient, may be obtained. |
