Electrically Insulative Performances of Ceramic and Clay Films Deposited via Supersonic Spraying

Supersonic spray coating techniques were applied to deposit ceramic and clay particles as films for use in electrical insulation. TiO2 and Al2O3 ceramics were aerosol-deposited under vacuum while kaolinite, montmorillonite, and bentonite clays were deposited by cold spraying in open air. The electrical resistivity of Al2O3 and TiO2 were ~109 and ~108 Ω cm, respectively. The resistivity of kaolinite and montmorillonite were ~1012 Ω cm. Bentonite showed the lowest electrical resistivity of ~109 Ω cm among the clays because of the high cation exchange capacity of the material. The film surface morphologies and mechanical properties in the form of hardness and scratchability were also investigated.