Wear Rate Evaluation of Sol-Gel TiO2-ZrO2 Films by Quantitative Depth Profile Analysis

Wear resistance of metallic materials can be improved by modifying their surface with different coating deposition techniques, one of which is the sol-gel technology. The sol-gel technology is simple, easy to adopt, requires low processing temperatures and leads to a high degree of purity of oxide coatings. In this paper, the erosive wear resistance of a ceramic nanostructured sol-gel TiO2-ZrO2 film consisting of three layers, deposited on a stainless steel substrate (X5CrNi18-10) by means of the dip coating technique has been studied. Quartz sand was used as an erodent with an impact angle of 30deg. Quantitative Depth Profile (QDP) analysis was used for the determination of the coating thickness and chemical composition before and after solid particle erosion. Glow Discharge Optical Emission Spectrometry (GDOES) was used for the analysis of the chemical composition of the bulk material (substrate) and the quantitative depth profiling of the deposited sol-gel film. The obtained results show that solid particle erosion of nanometric films can be monitored by depth profiling of the deposited sol-gel film

EFFECTS OF CONCENTRATION AND UV RADIATION WAVELENGHTS ON PHOTOLYTIC AND PHOTOCATALYTIC DEGRADATION OF AZO DYES AQUEOUS SOLUTIONS BY SOL-GEL TiO2 FILMS

The photocatalytic and photolytic degradation of anionic azo dyes Methyl Orange and Congo Red dye aqueous solutions was investigated in glass reactors with/without TiO2 films that were irradiated with UV light. Two nanostructured sol-gel TiO2 films were prepared by means of the dip-coating technique with and without of polyethylene glycol (PEG) as a structure-directing agent. Experiments were carried out by varying the concentration of dyes, TiO2 films and sources of UV radiation. The concentrations of dyes were 0.0125 mmol L-1, 0.025 mmol L-1 and 0.05 mmol L-1; the wavelengths of the incident ultraviolet light were predominantly 254 (UV-C) and 365 nm (UV-A). In the presence of TiO2 film UV-C radiation showed higher degradation efficiency for both dyes than UV-A radiation. Also, UV-C radiation without TiO2 photocatalyst was capable of degrading both dyes, while UV-A radiation alone did not show a potential for dyes degradation. Higher photoactivity showed TiO2 film with addition of PEG