Abstract
To provide the polyethylene terephtalate (PET) plastic material with photocatalytic property, anatase TiO2 powders were plasma sprayed under various plasma spraying conditions. The effects of spraying parameters and surface morphology of substrates such as PET and PET pre-coated with Cu on the microstructure, phase composition and photocatalytic activity of TiO2 coating were systematically studied. The photocatalytic activity of the TiO2 coating was evaluated by the decomposition test of acetaldehyde gas. From the experimental result, it was found that fabrication of TiO2 coating was possible on PET substrate at arc currents of 200, 300 and 400A. The TiO2 coatings were thicker with increasing arc current. However, the coating was not attained when the plasma spraying was carried out on steel substrate even at a high arc current of 400 A. In case of plasma spraying on PET substrate pre-coated with Cu, the coating was locally formed at the arc current of 200 A. At the current of 300 A, the coating was attained. It was found that all fabricated TiO2 coatings exhibited photocatalytic activity regardless of undercoat materials and spraying parameters from the acetaldehyde decomposition test. Even coatings with thin and locally formed layers also showed the same photocatalytic performance as other thick coatings. From the XRD analysis, the reason for the efficient photocatalytic activity in the coatings was due to the high anatase phase content.