Analysis Of Radiation Property And Influencing Factors Of Thermochromic Functional Material

Block thermochromic sample of La_0.7Ca_0.2Sr_0.1MnO₃ prepared by using solid-state reaction method is studied.The crystal structure of which is analyzed by XRD,also the element is analyzed by EDS,and the lamellar manganite is prepared by using standard ceramic technique.The thickness of it is 500μm,and the superficial roughness reach as low as 0.09μm.Temperature dependence of emittance of La_0.7Ca_0.2Sr_0.1MnO₃ material is studied from 243 to 343K.Result shows that the emittance increases monotonously with increasing temperature,and has a considerable change around the transformable temperature of metal-insulator.Effect of the mean grain size of raw material and calcining heat on the grain size of the block perovskite manganese oxide that after sintering is studied in this thesis.Further,the relation between the radiation characteristic of thermochromic material and grain size is analyzed.The phenomenon that block La_xCa_ySr_1-x-yMnO₃ turn to powder when put on air condition for a few days is improved from the aspect of calcining technics.Which perfect the prepared method of thermochromic material.Besides,based on the prepared techniques of lamellar material in existence.Take the block perovskite manganese oxide of La_0.7Ca_0.2Sr_0.1MnO₃ that has favorable characteristic of thermochromic variable emittance as butt,using electron beam evaporation method prepare lamellar sample on a stainless steel underlay,thickness of it is 300nm.Composition and emittance performance of the sample that fore-and-aft heat treatment process is measured by using emittance instrument.Much difference is found bewteen the lamellar sample and raw block material.