Behavior of TiO2 coating formation on PET plate by plasma spraying and evaluation of coating's photocatalytic activity

To examine the coating formation behavior on plastic material, that is, polyethylene terephthalate (PET), and allow for the fabrication of the photocatalytic coating on it, plasma spraying was carried out with anatase TiO2 powder. The effect of spraying parameters on the microstructure of TiO2 coating, fraction of melted TiO2 particles and surface temperature of PET substrate was investigated. The structure of the coating was also characterized by XRD. The photocatalytic property of the coatings was evaluated. The result shows that sprayed coating on PET could be divided into two types. One is that TiO2 coating is fabricated on PET plate and another is that TiO2 particles are implanted into PET. According to the fraction of melted TiO2 particles, the former was about 60% and the latter was approximately 10%. In both cases, it was also found that the surface of PET substrate was melted. Anatase ratio in the TiO2 coatings prepared under the specific spraying conditions, which exhibited good photocatalytic activity, was between 25% and 100%.