Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scann...Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.展开更多
The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosi...The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosion resistance of conversion films was analyzed by electro interstitial scanning （EIS）. The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.展开更多
Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generat...Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films'on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.展开更多
The etching technique using Ce is a convenient and fast method for polishing and shaping diamond films. In this study, the influence of polishing parameters such as polishing temperature and time on the surface crysta...The etching technique using Ce is a convenient and fast method for polishing and shaping diamond films. In this study, the influence of polishing parameters such as polishing temperature and time on the surface crystallinity and phase composition of diamond films was thoroughly investigated via the analysis of Raman spectra such as FWHM and ID/IG. Moreover, the issue on the graphitization of diamond after polishing with Ce was further researched through the detailed study of the depth distribution of Raman data including FWHM and ID/IG, and a result completely different from the hot-iron metal polished ones was obtained. The results showed that polished diamond films had considerably higher diamond content than those before polishing, and not a bit of graphitization was found in the polished ones, owing to a higher solubility of carbon in rare earth metal Ce than that in transition metals, and the original crystallinity of the films polished with Ce did not deteriorate.展开更多
Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt background and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The c...Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt background and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The cathodic reaction mechanism of the molten salt background was: O-2(-)+e <----> O-2(-2); O-2+2NO(3)(-) --> 2NO(2)(-)+2O(2). According to the results of SEM and XPS, cerium oxide film, which is composed of CeO2, can form on the nickel electrode at - 1.850 V vs. Ag/AgNO3 (0.1 mol/L) reference electrode.展开更多
Zn and Co multi-doped CeO2 thin films have been prepared using an anodic electrochemical method. The structures and magnetic behaviors are characterized by several techniques, in which the oxygen states in the lattice...Zn and Co multi-doped CeO2 thin films have been prepared using an anodic electrochemical method. The structures and magnetic behaviors are characterized by several techniques, in which the oxygen states in the lattice and the absorptive oxygen bonds at the surface are carefully examined. The absorptive oxygen bond is about 50% of the total oxygen bond by using a semi-quantitative method. The value of actual stoichiometry δ′ is close to 2. The experimental results indicate that the thin films are of a cerium oxide-based solid solution with few oxygen vacancies in the lattice and many absorptive oxygen bonds at the surface. Week ferromagnetic behaviors were evidenced by observed M-H hysteresis loops at room temperature. Furthermore, an evidence of relative ferromagnetic contributions was revealed by the temperature dependence of magnetization. It is believed that the ferromagnetic contributions exhibited in the M-H loops originate from the absorptive oxygen on the surface rather than the oxygen vacancies in the lattice.展开更多
The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electrolu...The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electroluminescence showed that only leading edge emission peak was observed for one sample and the leading and trailing edge emission peaks were observed for another in a half period of sinusoid applied voltage. This difference is related to the influences of sulphur vacancies on the excitation and emission processes. The leading edge emssion is dominated by discrete luminescence caused by direct impact excitation and the trailing edge emission and a part of leading edge emission belong to recombination luminescence caused by impact ionization and delocalization.展开更多
文摘Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.
文摘The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosion resistance of conversion films was analyzed by electro interstitial scanning （EIS）. The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.
基金The work was supported by Hong Kong RGC CERG9040344 and 9040412, RGC / Germany Joint Schemes9050084 and 9050150, and CityU S
文摘Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films'on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.
文摘The etching technique using Ce is a convenient and fast method for polishing and shaping diamond films. In this study, the influence of polishing parameters such as polishing temperature and time on the surface crystallinity and phase composition of diamond films was thoroughly investigated via the analysis of Raman spectra such as FWHM and ID/IG. Moreover, the issue on the graphitization of diamond after polishing with Ce was further researched through the detailed study of the depth distribution of Raman data including FWHM and ID/IG, and a result completely different from the hot-iron metal polished ones was obtained. The results showed that polished diamond films had considerably higher diamond content than those before polishing, and not a bit of graphitization was found in the polished ones, owing to a higher solubility of carbon in rare earth metal Ce than that in transition metals, and the original crystallinity of the films polished with Ce did not deteriorate.
基金[The project was financially supported by the National Science Foundation of China.]
文摘Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt background and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The cathodic reaction mechanism of the molten salt background was: O-2(-)+e <----> O-2(-2); O-2+2NO(3)(-) --> 2NO(2)(-)+2O(2). According to the results of SEM and XPS, cerium oxide film, which is composed of CeO2, can form on the nickel electrode at - 1.850 V vs. Ag/AgNO3 (0.1 mol/L) reference electrode.
基金supported by the Natural Science Foundation of Zhejiang Province,China(Grant No.LY12A01002)the National Natural Science Foundation of China(Grant Nos.11204058 and 21073162)the Hangzhou Dianzi University,China(Grant No.KYF09150603)
文摘Zn and Co multi-doped CeO2 thin films have been prepared using an anodic electrochemical method. The structures and magnetic behaviors are characterized by several techniques, in which the oxygen states in the lattice and the absorptive oxygen bonds at the surface are carefully examined. The absorptive oxygen bond is about 50% of the total oxygen bond by using a semi-quantitative method. The value of actual stoichiometry δ′ is close to 2. The experimental results indicate that the thin films are of a cerium oxide-based solid solution with few oxygen vacancies in the lattice and many absorptive oxygen bonds at the surface. Week ferromagnetic behaviors were evidenced by observed M-H hysteresis loops at room temperature. Furthermore, an evidence of relative ferromagnetic contributions was revealed by the temperature dependence of magnetization. It is believed that the ferromagnetic contributions exhibited in the M-H loops originate from the absorptive oxygen on the surface rather than the oxygen vacancies in the lattice.
文摘The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electroluminescence showed that only leading edge emission peak was observed for one sample and the leading and trailing edge emission peaks were observed for another in a half period of sinusoid applied voltage. This difference is related to the influences of sulphur vacancies on the excitation and emission processes. The leading edge emssion is dominated by discrete luminescence caused by direct impact excitation and the trailing edge emission and a part of leading edge emission belong to recombination luminescence caused by impact ionization and delocalization.
