Study On Structure Design And Performance Of Solar Energy Selective Absorption Coatings Of Carbide Cermet

In recent years, the energy and environment issues is increasingly serious, many countries in world have increased input and research in the renewable source, solar energy is the most abundant renewable resource, which has unique advantages and great potential for development. Compared with other energy, it is safe and reliable, has no noise, no pollution, and no consumption of fuel, these advantages are unmatched by conventional energy, therefore, it is very important to develop solar energy.One of the most critical technologies is preparing a selective absorption coating which has high absorptivity, low emissivity, stable performance, excellent weatherability. this paper summarized the basic types, absorption mechanisms, preparation methods, the latest research results at home and abroad, combine with the trend of solar thermal power generation development, then solar spectra selective absorption coating were prepared using the thermal spay technique.Firstly, it selected WC-12Co,NiCr-Cr3C2 powder, different thermal physics property WC-12Co and NiCr-Cr3C2 solar spectrum selective absorbing coatings were deposited by HVOF, and The surface morphology and phase structure were studied by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The research showed that coatings deposited by HVOF all possess a low porosity and dense structure, compared with micron and submicron structure WC-12Co coating, nano structure WC-Co coating which was composed of WC, Co and a few Of W2C was oxidized and decarbonized more seriously, phase structure of NiCr-Cr3C2 coating is mainly composed of NiCr,Cr3C2,Cr7C3.Secondly, absorptivity and emissivity were tested respectively by UV-VIS-NIR spectrophotometer and infrared spectrometer, and was also researched. The results showed that absorptivity and emissivity were affected by original size of powder,surface state of coating,the metal content and, however, the high infrared reflectance had no effect on it, In the three different original size of WC-12Co coatings, original size changed from the micron size to submicron size, its absorptivity increased and emissivity reduced, however, when the original size changes from submicron size to the nano size, its absorptivity dropped faster than emissivity.Thirdly, optical performance which was affected by the surface state of coating was studied, by comparing different roughness of submicron structure WC-12Co coating, the lower the roughness, the higher the absorptivity.Fourthly, two different metal content of NiCr-Cr3C2 coating were studied, the lower the content of NiCr metal alloy, the higher the absorptivity and emissivity.Finally, performance of high temperature oxidation and weathering resistance of submicron structure WC-12Co coating were studied, after two mouths' test under atmospheric environment, the coatings didn't fall off or break, and also after high temperature resistance experiment, the main phase of the coating and the coating's absorptivity and emissivity had no change basically, it not only demonstrate good absorptivity, but also good stability under high temperature.Considering the results of the above researched all-around, the solar spectrum selective absorbing coating holds excellent performance which is prepared by HVOF.