Preparation and Investigation of Nano-TiO₂-Modified Silicone-Based Reflective Thermal Insulation Coatings

A nano-TiO₂-modified silicone-based reflective thermal insulation coating is successfully synthesized. The influence of the nano-TiO₂ content on the microstructure, adhesion strength as well as near-infrared reflectivity (NIR) of the coatings before and after heat treatment is investigated. The results demonstrate that the coating is an organic/inorganic composite coating composed of muscovite, rutile-phase titanium dioxide and an organosilicon binder before heat treatment. The addition of an appropriate amount of nano-TiO₂ helps fill the pores in the coating, resulting in a dense coating and improved adhesion. Meanwhile, due to the reduced average size of the pigment, the reflectance of the coating is maintained or enhanced. When the addition amount is 5.0 wt.%, the coating achieves the highest bonding strength of Grade 1 with a reflectivity of 0.830. After heat treatment at 1000 °C for an hour, the coating transforms into an inorganic coating composed of partially melted muscovite and rutile-phase TiO₂. The nano-TiO₂ promotes the formation of a molten phase, which further increases the coating density and makes the surface smoother. Consequently, the coating’s bonding strength and reflectance are further improved, reaching Grade 0 and 0.945 respectively.