Prepared Method And Radiative Properties Of The Microstructure Surface Thrmochromic Thin Film

When the feature size of the materials is consistent with the radiation wavelength, its radiation characteristics will exhibit many physical effects compared with traditional radiation characteristics, the object of thermal radiation energy can be selected control. Study on the thermochromic properties on the block material structure perovskite manganese oxides has made great progress, but its thermal radiation properties of thin film morphology is obviously insufficient, cannot be used efficiently in spacecraft thermal control technology. This paper tries to analyze and solve this problem from the microstructure perspective.This paper simulated the reflectance properties of the La0.8Sr0.2MnO3 thermochromic films with one-dimensional gratings (Containing aluminum transition layer and without transition layer) and two-dimensional square hole arrays, then by calculating and analyzing of the different periodic and groove depth on the thermochromic film caused thermochromic properties. The calculation results show that the radiation ability of the microstructure thermochromic film has obvious enhancement and can improve the thermochromic properties. The decrease of the microscale, the increase of groove depth and aluminum transition layer lead to the thermal radiation properties of thin film are improved. As a result of the theoretical simulations show microstructures can improve thermochromic film thermochromic properties, followed by experiments to validate the feasibility of theory.Preparation of one-dimensional grating and the microstructure of the two-dimensional sqare hole arrays by means of the photoetching technique on the surfaces of single-crystal Si substrate, and through the etching process to study the effects on etching morphology, the La0.8Sr0.2MnO3 thermochromic films is deposited on the microstructure of silicon by RF magnetron sputtering and the films step coverage problems are improved by rotating the substrate and heating the substrate.Using the SEM, EDS, VSM to detect the surface topography, composition elements properties and magnetic transport properties. The SEM measurements showed that the Si substrate has good microstructure morphology. The EDS results showed that, in addition to oxygen element deficiency, the proportion of other elements in the film is consistent with the theory of stoichiometric ratio. The VSM results showed that, the one- and two-dimensional microstructure of the La0.8Sr0.2MnO3 thin films are ferromagnetic to paramagnetic transition obviously, the transition temperature Tc are 300K and 270K respectively.The optical properties of the microstructure thin films prepared in the experiment are tested. Then the thermal radiation characteristics of the films are obtained by calculation. Study on effect of microstructure size on the radiation properties of thin films and compared with simulation results. The results of the experiment and simulation shows that microstructure indeed can enhance the radiation ability of thermochromic thin films. The thermal radiation properties of thin film are improved with the increase of groove depth.