Preparation Of The Weather-resistant Solar Selective Absorbing Coating By Magnetron Sputtering

Recently, the development of the solar water heater and its practical application is very fast, because there are many approaches to utilize solar energy and the simplest manner is the photo-thermal conversion. Water heater collect with the whole vacuum glass tube hot device account for the majority, and flat plate solar heat collectors is less. But what we can not ignore is that solar water heater is a development trend of high-efficiency solar energy material and building integration. Now most countries take the flat plate solar heat collectors for integrating the solar water heater and building. But in our country, there are two flaws for flat plate solar heat collectors, one is that the absorbing material is not a selective material, so the material have a high emissivity in high temperature, the other one is the process of produce such as brushing and galvanization will pollute the environment, some process of produce will face the problem that the film is shelled from the surface. For solving the problem of the solar heating water device especially flat plate solar heat collectors, the key is find a good process to produce to produce a solar selective absorbing film which have a good absorbing efficiency, at the same time the process will not pollute the environment and also can be applied to the production with the big scale. Nowadays many countries are devoted into the research and preparation of solar selective absorbers with good properties by simple and low cost process. In this paper, the theory of metal-ceramic solar selective absorbers and the technology of magnetron sputtering and also their developments are introduced. We started the research of solar selective absorbers to questions that there are selective absorbing film which have a good absorbing efficiency, at the same time the process will not pollute the environment and also can be applied to the production with the big scale. Nowadays many countries are devoted into the research and preparation of solar selective absorbers with good properties by simple and low cost process. In this paper, the theory of metal-ceramic solar selective absorbers and the technology of magnetron sputtering and also their developments are introduced. We started the research of solar selective absorbers to questions that there are disadvantage in domestic preparing process and the properties of absorbers for flat plate solar collectors.Multilayer metal—ceramic graded index TiNxOy/SiO2absorbers were prepared by d. c reactive magnetron sputtering process from a Ti target in an atmosphere of Ar/N2/O2, which can be applied to the flat plat solar heat collectors and photo-thermal functional building materials. Different metal fraction in the films can be obtained by controlling the flux of N2and O2. Based on experiments and analysis, the process affecting factors and the properties of the films were summarized. Stable process was achieved by controlling proper sputtering conditions. The films were analyzed by XRD, AFM. And the absorptance, emittance and optical constants of the films were measured.