A plasma sprayed superhydrophobic coating prepared with Al@WO3 core-shell powder and photocatalytic degradation performance

摘要

The insufficient hydrophobicity due to difficulty in producing surface nanostructures hinders the application of thermal spraying technology for metal-based superhydrophobic coatings. In this paper, the hydrophobicity of an Al-based composite coating prepared by plasma spraying was innovatively improved by WO3 nanoparticles electroless plated on Al spraying powders and nano-oxides produced by chemical vapor deposition induced by plasma spraying (PS-CVD). Results showed that Al@WO3 core-shell powder was fabricated as feedstock. A mixture of two nano-products (Al2O3 and W) was formed on the surface of the coating and the reason may be that aluminum vapor reduced WO3 to W. The effects of plasma arc current and H-2 flow rate on surface morphology and wettability of the as-prepared coating were investigated. It was found that the increase in H-2 flow rate and plasma arc current enhanced the generation of surface nano-products by PS-CVD, and thus improved the coating hydrophobicity. However, extremely high temperature may result in the refusion of nano-products. The highest water droplet contact angle (WCA) reached 157.0 +/- 1 degrees and the lowest water droplet sliding angle (WSA) was 7.5 +/- 1 degrees. Finally, the photocatalytic activity of the coating was tested by its performance in the degradation of methyl orange, and it was found that acidic conditions facilitated the degradation performance. The superhydrophobicity and photocatalysis performance demonstrate the potential use of the as-prepared coating in antibacterial and antifouling fields.