Functionalization of suspension sprayed HVOF TiO2 coatings by direct laser interference patterning

For more than one decade, suspension spraying has been gaining interest for the development and manufacture of coatings for wide range of applications such as photocatalysis, thermal barrier coatings, wear resistance, biomaterials or superhydrophobicity. Even though these coatings are already promising, a modification of their surface properties can further improve their functionality and lifetime in order to meet the growing requirements on the coating demands. Direct laser interference patterning (DLIP) is a versatile laser technology which allows fabricating microstructures with high flexibility and therefore designing surface properties on a large diversity of materials, including metals, polymers, ceramics and coatings. In this contribution, DLIP technology was applied to texture the surface of suspension sprayed high velocity oxy-fuel (HVOF) TiO2 coatings. In particular, a nanosecond-pulsed laser has been used to produce cross-like patterns and the effect of laser parameters on the coating properties was investigated. The coatings were characterized by means of scanning electron microscopy, Raman spectroscopy and UV-Vis-IR measurements, and the influence of the laser treatment on the photocatalytic activity and wettability behavior has been investigated. The results showed that the DLIP technology is suitable for designing and tailoring of the surface properties of the suspension sprayed coatings.