Papers by Author: Zhao Hua Jiang

Abstract: A ceramic coating grows on the surface of Q235 carton steel in situ by the micro-arc oxidation method and the silicate electrolyte system; and the phase composition, surface topography and elementary composition of the ceramic coating are analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (EDS). The results show that the ceramic coating growing on the surface of Q235 carton steel in situ presents an irregular porous structure; and the electrolyte and the element in the basal body exist in the ceramic coating in the form of amorphous state. And then, the author degrades the rhodamine B solution by the home-made ceramic coating and H₂O₂ Fenton system, so that the degradation rate of the rhodamine B solution can reach 97%; and meanwhile, the degradation rate is not reduced along the increased using times.

Abstract: Ceramic coatings containing graphite were prepared on Q235 carbon steel by plasma electrolytic oxidation (PEO) in aluminate electrolyte with graphite dispersed in electrolyte. The microstructure and properties of the coatings including phase composition, surface and cross section morphology, thickness and bonding strength were characterized. The results showed that the coating consisted of FeAl2O4, Fe3O4 and a certain amount of graphite. The coating was typically characterized by micro pores and ball-shaped round grains distributed on the surface. With increasing the treating current density, the pores became bigger and the ball-shaped round grains became more. Coatings obtained with various current densities showed a good interface between the coating and substrate. The bonding strength of the coatings decreased a little when increasing the current densities, the values of which were all above 20MPa. The coating grew both inwards and outwards to the substrate surface. With increasing the treating current density, the consumption of substrate gradually increased but the whole thickness was not strongly affected by the current density and the value was about 115 μm.

Abstract: Graphene-metal oxide composites as supercapacitor electrodes combine the large pseudocapacitance of metal oxides with the fascinating electrical and mechanical properties and large surface area of graphene. The synthetic methods for composites are reviewed, including in-siu synthesis, solution mixing, hydrothermal method, microware irradiation and electrochemical deposition. Among these techniques, the hydrothermal method offers an effective and simple way to anchor metal oxides on the 2D graphene sheet uniformly. Consequently, the composites exhibit high capacity, high rate capability and well reversibility, presenting promising prospects as supercapacitor electrode material.

Abstract: Self-lubricative ceramic coatings were prepared on Q235 carbon steel by plasma electrolytic oxidation (PEO) in aluminate electrolyte containing graphite. The microstructure of the PEO coatings were examined. Influence of graphite in electrolyte on the coating growth properties was analyzed according to the voltage vs. time plots. Effect of graphite concentration on the properties of the coatings such as bonding strength, surface roughness and thickness were studied. The tribological behavior of the coating was primarily evaluated.The results showed that the self-lubricative coatings consisted of FeAl₂O₄, Fe₃O₄ and a certain amount of graphite. With increasing the concentration of graphite in the electrolyte, the coating growth gradually became stable with lower breakdown voltage and end voltage. The bonding strength and the thickness of the coating were not strongly affected by the graphite concentration whose value remained approximately 19Mpa and 110μm, respectively. With increasing the graphite concentration, the surface roughness first decreased and then increased a little. The friction coefficient of the coatings also varied with the concentration of graphite. When the concentration of graphite was 8 g/l, the tribological property of the coatings was the most excellent with the friction coefficient bellow 0.1.

Abstract: A complex of Eu(Ⅲ), HTTA and TPPO was synthesized in alcohol (HTTA= 2-Thenoyltrifluoroacetone and TPPO=Triphenyl phosphine oxide )and its corresponding single crystal was obtained. The complex was characterized by IR,UV, X-ray single crystal diffraction.The photoluminescent and electroluminescent properties of the complex were studied. The results showed that the spectra structure characterization is consistent with that of single-crystal diffraction. The complex exhibited ligand-sensitized red emission, and it has higher sensitized luminescent efficiency and good thermal stability.In device ITO/PVK/ Eu(TTA)3(TPPO)2/Al, Eu3+ may be excited by intramolecular energy transfer from ligand as observed by electroluminescence. The main emitting peak at 614 nm can be attributed to the europium of ⁵D₀→⁷F₂ of Eu ³⁺ ion and this process results in the enhancement of red emission from electroluminescence device. The present study may be important and helpful for the development of red color rare earth display applications.

Abstract: Carbon coated N-doping of TiO₂ nanotube films were successfully prepared by a two-step process of anodization and gas thermal penetration. The morphologies and structures of composites were characterized by SEM, XRD, XPS and Raman spectroscopy analyses, respectively. The results show that graphitized carbon deposited on the surface of TiO₂NTs nanotubes under gas thermal penetration conditions, by which N atoms are incorporated into the lattice of TiO₂NTs through substituting the site of oxygen atoms. Such Carbon coated N-doping of TiO₂ nanotube films presents the enhance absorption in visible region. The photo catalytic tests show that the prepared films at 600°C reveal higher photocatalytic activity for splitting of water than other samples.

Abstract: Owing to the defects of the fixed TiO2 photocatalysts, the research employed the approach of anodic oxidation to produce high efficiend N-TiO2/Ti ceramic film oxidized on the surface of titanium, in order to make the absorbable spectrum of light catalyst spread to the visible region and constrain the high recombination rate of electron-hole pairs during photoreaction. The surface appearance and the distribution of elements have been checked with scanning electron microscopy and EPMA. The microcrystal structure of the films has been checked with XRD. The results showed that the main components of nitrogen-doped catalyzer were rutile and anatase, meanwhile, the nitrogen element distributing on the film was fairly uniform. Films of N-TiO2 photocatalysis reduction K2CrO4 revealed that with the amount of N-contained increased, the rate of reduction K2CrO4 decreased under ultraviolet light while that increased under visible light. It was found that the highest reduction rate of K2CrO4 was achieved through an optimal (NH4)2S2O8 dosage of 0.4g/L in ceramic film prepared processes.

Abstract: The coatings containing zirconia were produced on LY12 Aluminium alloy by micro-arc oxidation in K2ZrF6 and NaH2PO2 solution. The composition, structure, hardness, friction and wear resistance and corrosion resistance of the coating were studied by XRD, SEM, EDS, ball-on-disk friction tester and electrochemical analyzer, respectively. The results show that coating was composed of m-ZrO2 and t-ZrO2. There were a large amount of Zr and O and a little Al, P and K in the coating. The thickness of coating prepared for 3h was 168μm and the maximum value of the hardness was up to 16.75GPa. The friction and wear resistance and corrosion resistance were improved, compared with the LY12 aluminium alloy substrate.

Abstract: With the approach of anodic oxidation, TiO2/Ti film doped with Cu2+ was produced in H2SO4 electrolyte mixed with CuSO4. The surface morphology and the roughness of the films were studied with atomic force microscopy. The phase composition of the films was studied by X-ray diffraction. The photocatalytic activity of the films was compared through the photocatalytic degradation rate of phenol. The relations of the photocatalytic activity to the concentration of Cu2+, the microstructure and the surface roughness of the film were investigated. The results showed that Cu2+ increased the surface roughness and restrained the growth of crystal. In addition, the phenol in aqueous solution was successfully photodegraded under visible light irradiation by Cu2+-TiO2/Ti film. The composition and structure of the film affected the catalytic activity greatly. Compared with TiO2/Ti film, the recombination rate of e- and h+ of Cu2+-TiO2/Ti film was decreased.

Abstract: The high efficient WO3-TiO2/Ti ceramic film was prepared on the surface of titanium by the approach of anodic oxidation in order to make the absorbable spectrum of catalyst spread to the visible region and restrain the high recombination rate of electron-hole pairs during photoreaction. The surface morphology and the distribution of elements were studied with scanning electron microscopy and energy dispersive spectroscopy. The phase composition of the films was investigated with XRD. The results showed that the main components in the coating were WO3, rutile TiO2 and anatase TiO2. The compound WO3-TiO2/Ti ceramic film enlarged the range of the reacting visible light and increased the absorbing intensity. The rhodamine B was successfully photodegraded under visible light irradiation by WO3-TiO2/Ti catalyst films. It was found that the highest degradation rate of rhodamine B was achieved through an optimal W dosage of 4.2 %(wt %) in WO3-TiO2/Ti ceramic film. It was also confirmed that the recombination rate of electron-hole pairs in WO3-TiO2/Ti ceramic film declined due to the existence of WO3 in TiO2/Ti ceramic film.