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 ZrSiO 4 powder, which hinders the formation of structurally stable film layers. During the high-energy milling process, the ZrSiO 4 -PE composite powder agglomerates suitably and exhibits adequate kinetic energy to produce a porous film. Despite its exceptional thermally insulating characteristics, the ZrSiO 4 -PE composite film demonstrates relatively poor adhesion properties. Consequently, an optimized quantity of Y 2 O 3 powder is blended to modulate the thermal insulating and mechanical adhesion properties of the porous coating films. The Y 2 O 3 -(ZrSiO 4 -PE) composite film (approximately 60 μm) exhibits low density (2.2 g/cm 3 ), low thermal conductivity (at ambient temperature, approximately 0.64 W/m∙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.