Preparation And Thermal Properties Of High Temperature Thermal Radiation Coatings

In this experiment,SiC and various transition metal oxides were used as high-emissivity fillers,and self-modified aluminum dihydrogen phosphate was used as a high-temperature-resistant binder to prepare a thermal radiation coating with both high infrared emissivity and excellent high-temperature resistance.The effects of filler composition ratio,different processing temperature and doping amount of rare earth oxide on the infrared emissivity and other properties of the coating were studied.Experiments show that the mass ratio of different components in the filler,the ratio of rubber to powder,the sintering temperature and the doping amount of rare earth oxides will have a certain impact on the performance of the coating.Using XRD,XPS,FT-IR,SEM,infrared emissivity and other characterization and testing methods to test and analyze the material composition,crystal structure,microstructure,surface ion valence state and infrared emissivity of the thermal radiation coating,revealing different The effect of the proportioning filler on the thermal radiation performance of the coating.With SiC and SiO₂ as high-emissivity fillers,and self-modified aluminum dihydrogen phosphate as binder,thermal radiation coatings with good performance were prepared by ball milling and high-speed stirring.The test results show that when the addition amount of chromium oxide green is 9%,the adhesive has the best film-forming property and high temperature resistance;when the rubber powder ratio is 1:1.75 and the proportion of SiC in the system is 60%,The infrared emissivity of the thermal radiation coating is the best,reaching 0.9.It has high emissivity and excellent adhesion,and has high bonding strength with refractory bricks;in addition,the coating has been tested for thermal shock resistance.In the experiment,the surface morphology remained relatively intact after 20 cycles of extreme heat and extreme cold.The thermal radiation coatings prepared with ZnO,Fe₂O₃and MnO₂ as fillers have higher infrared emissivity and better high temperature resistance.The test results show that the product of the coating with ZnO as the main component is mainly Zn Fe₂O₄.When the mass proportion of ZnO is 20%,the infrared emissivity of the coating is the best,which is 0.93;when the mass proportion of MnO₂ is 40%,the coating has the best infrared emissivity.The infrared emissivity of the coating is the highest,which is 0.92.With the further increase of the MnO₂ content,the infrared emissivity of the coating will decrease.It is speculated that this phenomenon is related to the homogeneity of the substances in the coating.Among the three sintering temperatures,the 1200℃.The thermal radiation coating sintered in the environment has the highest infrared emissivity After the SEM test of the three coatings,it is found that the spinel structure generated in the 800℃environment is not complete and the infrared emissivity is the lowest,and the 1000℃environment Although the spinel structure begins to form,the grain integrity and the richness of the structure level are not as good as the coating sintered in the 1200℃environment.The coating sintered in the 1200℃environment has the highest infrared emissivity and good adhesion;For the rare earth oxide Y₂O₃,the infrared emissivity of the coating is the highest at 2%,which is 0.935.The thermal radiation coatings prepared with NiO,Fe₂O₃and MnO₂ as the main fillers have relatively good practical application value.The test results show that when the content of NiO in the raw material is 30%,the infrared emissivity of the coating is the highest（0.94）,and it also has excellent high temperature resistance and adhesion.The coating was applied on the stainless steel basin,and the water-boiling test was performed with the basin without coating.The test results showed that the energy-saving efficiency of the thermal radiation coating prepared in the experiment was about 26.4%,which has a relatively good practical application prospect.