### Titanium Dioxide Coatings Sprayed by a Water-Stabilized Plasma Gun (WSP) with Argon and Nitrogen as the Powder Feeding Gas: Differences in Structural, Mechanical and Photocatalytic BehaviorTitanium Dioxide Coatings Sprayed by a Water-Stabilized Plasma Gun (WSP) with Argon and Nitrogen as the Powder Feeding Gas: Differences in Structural, Mechanical and Photocatalytic Behavior

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 Author Ctibor, P. ♦ Pala, Z. ♦ Sedláček, J. ♦ Štengl, V. ♦ Píš, I. ♦ Zahoravá, T. ♦ Nehasil, V. Source SpringerLink Content type Text Publisher Springer US File Format PDF Copyright Year ©2012 Language English
 Subject Domain (in DDC) Technology ♦ Engineering & allied operations Subject Keyword bandgap ♦ photocatalysis ♦ resistivity ♦ spectroscopy ♦ TiO$_{2}$ ♦ Operating Procedures, Materials Treatment ♦ Surfaces and Interfaces, Thin Films ♦ Characterization and Evaluation of Materials ♦ Tribology, Corrosion and Coatings ♦ Analytical Chemistry Abstract Titanium dioxide coatings were sprayed by a water-stabilized plasma gun to form robust self-supporting bodies with a photocatalytically active surface. Agglomerated nanometric powder was used as a feedstock. In one case argon was used as a powder-feeding as well as coating-cooling gas whereas in the other case nitrogen was used. Stainless steel was used as a substrate and the coatings were released after the cooling. Over one millimeter thick self-supporting bodies were studied by XRD, HR-TEM, XPS, Raman spectroscopy, UV-VIS spectrophotometry and photocatalytic tests. Selected tests were done at the surface as well as at the bottom side representing the contact surface with the substrate during the spray process. Porosity was studied by image analysis on polished cross sections where also microhardness was measured. The dominant phase present in the sprayed samples was rutile, whereas anatase was only a minor component. The hydrogen content in the nitrogen-assisted coating was higher, but the character of the optical absorption edge remained the same for both samples. Photoelectron spectroscopy revealed differences in the character of the O1s peak between both samples. The photocatalytic activity was tested by decomposition of acetone at UV illumination, whereas also the end products—CO and CO$_{2}$—were monitored. The nitrogen-assisted coating was revealed as a more efficient photocatalyst. Certain aspects of a thermal post-treatment on the coatings are discussed as well. Color and electrical conductivity are markedly changed at annealing at 760 °C, whereas only very small changes of the as-sprayed coating character correspond to annealing at 500 °C. ISSN 10599630 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 2012-02-09 Publisher Place Boston e-ISSN 15441016 Journal Journal of Thermal Spray Technology Volume Number 21 Issue Number 3-4 Page Count 10 Starting Page 425 Ending Page 434