The Systhesis Of Bifunctional Poss Andits Effect On The Properties Of Hifh Emission Materials

Infrared radiation material, which is widely used for industrial furnace and especially aerospace industry. In aerospace engineering, research on the thermal protection system(TPS) becomes a hotspot due to its importance for the spacecraft returning to the ground process, which generates a great deal of heat. If the heat cannot escape from the spacecraft timely, the damage for the spacecraft will be lethal. High emissivity material can transfer the heat energy from the substrate surface to the environment in the form of radiation dissemination, helping to reduce the surface temperature. Therefore, the overheating of the spacecraft issue could be solved by high emissivity coating on the spacecraft surface. Moreover, the current research focus is the radiation efficiency and thermal shock resistance improvement for the coating.In this study, we prepared a multi-function coating with high radiative efficiency and thermal shock resistance. POSS system was used as a binder, while the main raw materials were Si C and Mo Si2. Transition-metal oxide was added to achieve a multicomponent composite while ball-milling method was used for the manufacturing process. The coating was made layer by layer in sequence of poss-collosol and paint to the ceramic substrates, following the heating procedure.Scan electron microscope was used to analyze cross-section for the surface coating. IR and X-ray diffractometry were used for the structure characterization. At last, the IR radiative efficiency and thermal shock resistance for this coating were also analyzed.The XRD pattern illustrated partly of the Si C and Mo Si2 were oxidized if the annealing temperature reached 800~1000 ℃. However, after the annealing at 1000℃, a blue coating was achieved with the increasing of Co Mo O4 relative content. We can see from the thermal shock resistance analysis, the best heating temperature is below400 ℃, with the heating rate of 5℃/min. For the selection of the binder, the bifunctional POSS-collosol had the best property while the thermal shock resistance could be improved by adding Zr O2 compound. The IR radiative data showed the additive of transition metal oxides(i.e., Si C-Mo Si2-Al2O3-Co3O4-Ni O-Zr O2), could help the IR radiative efficiency improvement under 400℃.