R. S. Lima, B. R. Marple, National Research Council of Canada, Boucherville, QC, Canada; H. Lee, Ajou University, SUWON, South Korea; S. A. Akbar, The Ohio State University, Columbus, OH
Titania (TiO2) coatings were produced using the high velocity oxy-fuel (HVOF) technique on Ti-6Al-4V substrates. The titania feedstock powder exhibited nanostructured morphology, formed by a successive agglomeration of individual nanostructured titania particles (spray-drying) smaller than 100 nm. The resulting coatings were dense (porosity <1%) and exhibited rutile and anatase as phases with percentages of ~75% and ~25%, respectively. These coatings were heat-treated in a H2/N2 environment at 700oC for 8h. During the heat-treatment nanostructured titania fibers were formed on specific surface regions of the coatings. The nanofibers formed by this “chemical or reaction-based texturing” exhibited diameters of 50-200 nm and lengths in the order to 1-10 mm. It is thought that engineering these surfaces at nano and micro-scales may lead to interesting applications of titania coatings related to (i) cell attachment/growth (for biomedical applications) and (ii) photocatalytic properties. The possible mechanisms of nanofiber formation are discussed.
Summary: Titania coatings were produced using HVOF on Ti-6Al-4V substrates. The titania feedstock powder exhibited nanostructured morphology. Nanofibers (50-200 nm diameter and 1-10 microns long) were texturized on the surface of the coatings. Engineering these surfaces at nano and micro-scales may lead to interesting applications related to biomedical and photocatalytic properties.
