| 摘要 |
PURPOSE:To improve the heat-resisting performance and raise the heat absorbing efficiency of a solar-heat absorbing element that is used in a solar heat utilizing water heater or the like, by forming a composite coating layer having fine particles or powder dispersed in a metal matrix between a base member and a selective absorption film. CONSTITUTION:A composite coating layer 3 is formed over the surface of a base member (for instance, made of copper or aluminum having a high heat conductivity) 2 of a solar-heat absorbing element 1. This composite coating layer 3 is obtained by dispersing fine particles 3b in a matrix 3a, and its surface presents fine ruggedness of the particles 3b. Here, the above-mentioned matrix 3a is made of a metal, and the particles 3b are metal powder. Further, a selective absorption film 4 is formed over the rugged surface of the coating layer 3 in the manner of leaving the fine ruggedness on its surface, so as to absorb near infrared rays effectively by causing irregular reflection of near infrared electromagnetic waves. Thus, it is enabled to raise the heat absorbing efficiency of the solar-heat absorbing element and to increase the heat-resisting performance of the same. |
