Low thermal conductivity and high durability porous thermal insulation coating via room-temperature spray coating process

Herein, an efficient approach using aerosol deposition (AD) is proposed to fabricate a porous ceramic film with high thermal insulating and adhesive properties. Polyethylene powder (PE) is incorporated to regulate the kinetic energy of the ZrSiO4 powder, which hinders the formation of structurally stable film layers. During the high-energy milling process, the ZrSiO4-PE composite powder agglomerates suitably and exhibits adequate kinetic energy to produce a porous film. Despite its exceptional thermally insulating characteristics, the ZrSiO4-PE composite film demonstrates relatively poor adhesion properties. Consequently, an optimized quantity of Y2O3 powder is blended to modulate the thermal insulating and mechanical adhesion properties of the porous coating films. The Y2O3-(ZrSiO4-PE) composite film (approximately 60 mu m) exhibits low density (2.2 g/cm(3)), low thermal conductivity (at ambient temperature, approximately 0.64 W/m center dot K), and excellent adhesion strength (37 MPa) attributes. This research offers valuable guidance for fabricating composite porous ceramic films with low thermal conductivity and high adhesion at room temperatures using AD.