Papers by Author: Wu Wen Luo

Abstract: The influence of heat-treated temperature and the CeO2 content on the chemical composition and the valence state of elements on surface of ZrO2-CeO2 thin films deposited on metal substrates has been studied by X-ray photoelectron spectroscopy. Results show that: elements of Fe, Cr, Zr, Ce exist in the form of their respective stable state, such as Fe2O3, (Fe0.6Cr0.4)O3, ZrO2, CeO2, when heat treated at 600°C and 700°C for 2h respectively; with the increase of heat-treated temperature, the area of oxygen with O1s peak corresponding to value of bonding energy 529.28ev increases, but the area of oxygen with O1s peak corresponding to value of bonding energy 531.7ev decreases.

Abstract: X-ray diffraction (XRD) method to measure the residual stress existing in the metal substrate surface layer was introduced and the sol-gel ZrO2-CeO2 thin film was successfully prepared on SUS304 stainless steel substrate by dip-coating process. The macro residual stress existing in metal substrate was analyzed by XRD. It turns out that the compressive stress existing in the metal substrate surface layer increases with the increase of heat-treated temperature. Based on the above study, colored stainless steels of high quality were prepared by sol-gel process.

Abstract: X-ray diffraction (XRD) method to measure the residual stress in the metal substrate surface layer and the medial oxide layer between thin film and metal substrate was introduced and the sol-gel TiO2-SiO2 thin film was successfully prepared on SUS304 stainless steel substrate by dip-coating process. The macro residual stress existing in metal substrate was analyzed by XRD. It turns out that the compressive stress existing in the metal substrate surface layer decreases with the raising of heat-treated temperature and that the compressive stress of metal substrate surface layer and the tensile stress of the medial oxide layer increase with the increase of the withdrawal speeds of the sol-gel dip-coating. Based on the above study, colored stainless steels of high quality were prepared by sol-gel process for the first time.

Abstract: Through X-ray photoelectron spectroscopy, by the aid of Ar+ sputtering, chemical composition and the valence state of elements on surface and at depth of TiO2-SiO2 thin films and metal substrates have been studied. Results show that: on surface, elements of Cr, Mn, Ti, Fe exist in the form of their respective stable state, but Si is unstable and exhibits stoichiometrical disturbance when heat treated at 800°C; at depth, after sputtering for 5 minutes and 17 minutes, elements of Cr, Mn, Ti and Ni exist in the form of their respective stable state, but Si and Fe are unstable and exhibit stoichiometrical disturbances; at depth, after sputtering for 57 minutes, all of the Cr, Mn, Ti, Si, Ni and Fe exist in the form of their respective stable state. Results of chemical composition and their content by weight percent of TiO2-SiO2 thin films and metal substrates reveal that: Fe, Cr, and Mn diffuse from metal substrates to the thin films in scale; Ni diffuses few and Si collects to the metal substrate surface

Abstract: Two-layer antireflective films were prepared on Na-Mg-Ca-Si glass substrate by sol-gel process starting from metal alkoxides: Si(OC2H5)4, Ti(OC4H9)4. The transmittance of glass was increased obviously (>95%), the reflective index was reduced to 1.95 through visible light range. TEM observation showed that SiO2 film is compactly joined to TiO2 film and TiO2 film to the substrate. TEM-EDX analysis of the films, film-substrate interface and substrate revealed that with the increase of Ti content, the content of Mg，Ca and Si decreases, however, the content of Na increases. The diffuse of Na+ from the substrate to the film is negative diffusion.