Papers by Author: Sang Mok Han

Abstract: Thin film photocatalysts of TiO2 coated on the glass were prepared to self-clean and eliminate air pollutants by spin coating process with Ti(OC3H7 i)4, including PEG. The surface structure of TiO2 films changed according to the molecular size of PEG. It was found that NOx was efficiently eliminated by the TiO2 film photocatalyst. The contact angle of water drop on the TiO2 films decreased to less than 10°. It revealed the hydrophilic property of TiO2 films. The morphology and the crystal structure of TiO2 films were affected most.

Abstract: ZrO2-SiO2 coatings deposited on 316 L stainless steel were prepared to protect chemically the substrates by sol-gel process using Zr(OC3H7 n)4/Si(OC2H5)4 as precursors. The influence of the ZrO2-SiO2 coatings on the corrosion resistance of the 316 L stainless steel was evaluated with the potentiodynamic polarization curves in deareated 15% H2SO4 solutions at 25, 40 and 50 °C . Comparative test was performed on uncoated one. The values of the electrochemical parameters explain how. ZrO2-SiO2 films increase the resistance of stainless steel against corrosion.

Abstract: Sol-gel coatings of TiO2 have been prepared from TiO2 sol and deposited by a dip-coating technique on 316L stainless steel sheets to study their electrochemical behavior in corrosive solutions. The influence of the coatings on the chemical corrosion of the substrate was evaluated by potentiodynamic polarization curves in different aqueous NaCl solution at 25°C. Comparative tests were performed on uncoated one. The thickness of the TiO2 coatings varied from 0.5~0.8 µm. The values of the electrochemical parameters allow for an explanation of the role of the TiO2 films in the increased resistance of stainless steel against corrosion in moderately aggressive environments.