Study On Hypothermia Presintering Prepare Infrared High Emissivity Ceramics Coating

When the spacecraft is working in the sky,it will produce a lot of heat. The heat reach to thousands of degrees Celsiusat,this heat one hand from the spacecraft fiction with the air. At the other hand from the spacecraft self heat when it is working.The spacecraft cannot proper function if the heat not dissipate. So it is important to let the heat be slaked. At present,one of the methods to solve this problem is use the high emissivity coating brush the surface of the spacecraft.The coating includes the transition coating、the low temperature glaze coating and the high emissivity coating.We use the POSS sol as the transition coating and the binder.The main raw material of the low temperature glaze coating contain Na2B4O7.10H2 O, SiO2, Al2O3 at the same time add CaO, ZnO and BaO to the raw material for make the performance better than before.The high emissivity coating raw material include Co2O3, NiO, Cr2O3 to make the function of the coating better. The current main research direction of high emissivity coating is to raise its emissivity.Test Performance of the coating from the FTIR, XRD, the function of against thermal shock, SEM-EDS the Performance of Radiation、the performance of isolate quantify of heat.From the results we can know the best coating. Through the FTIR and XRD we know the structure of phase.We know the performance of the coating when it in high temperature and suddently in low temperature from the test of the function of against thermal shock. Through the test of Radiation,SEM, EDS, against thermal shock we can understand the performance of the coating.According to the data of Radiation Performance : Si-Mo-Al-Co-Ni-Cr series than Si-Mo-Al-Co-Cr series the emissity higher reach 0.71 at 5μm when at 800℃. Between 23μm-25μm,the emissity of Si-Mo-Al-Co-Ni-Cr series can reach 0.97. According to the data of XRD : Ba2B2O5 spinel structure after 800℃ sintering, which greatly increased the emissivity and thermal shock resistance of the coatings The results showed, the ratio of 1:2 of POSS50 and POSS60 added into the material will have the best the thermal resistance ability and film forming temperature.