Effect of high-temperature compositional and structural evolution of the polysiloxane coating with glass/Al powder on the infrared and mechanical properties

A low infrared emissivity coating was prepared by using Al powder as an infrared functional pigment, and polysiloxane and glass powder as organic and inorganic binders, respectively. Thermogravimetric analysis, fourier transform infrared spectrometer, thermo-mechanical analyzer, and field emission scanning electron microscope were used to examine the coatings compositional and structural evolution at high-temperature. The infrared emissivity of the coating at high temperature was investigated in detail, which based on the evolution mechanism. Additionally, the effects mechanism of composition changes at high-temperature on the mechanical behavior of the coating was systematically studied, and the wind erosion resistance temperature was measured by self-design instrument. The result shows that the infrared emissivity of coating was low to 0.28 (within 7.5 − 14 μm) at 590 °C, owing to the polysiloxane decomposition, regular arrangement of surface Al powder. Moreover, the thermal pre-treatment could be reduced the shrinkage stress mainly results from the polysiloxane decomposition and glass powder melted within 400−520 °C, and the wind erosion resistance temperature was enhanced obviously after pre-treatment at 500−600 °C. The coating has potential applications in heat-resistance equipment, surface energy saving technology, or spacecraft infrared stealth owing to the excellent high-temperature infrared radiation suppression, thermal protection and wind erosion resistance property.