Hot-dip galvanized(HDG)steel sheets were treated for 30 s?24 h by the rare earth aqueous solution containing 20 g/L Ce(NO3)3·6H2O,and the growth behavior and corrosion resistance of the rare earth film were inves...Hot-dip galvanized(HDG)steel sheets were treated for 30 s?24 h by the rare earth aqueous solution containing 20 g/L Ce(NO3)3·6H2O,and the growth behavior and corrosion resistance of the rare earth film were investigated by SEM,EDS,AES and NSS.The results reveal that the rare earth film becomes thick while the mass gain of the samples does not distinctly change due to the zinc dissolution with the increase of treatment time.The film grows up more quickly and is apt to cracking in the vicinity of zinc grain boundaries,and eventually the film partly warps and flakes off with increasing film thickness.The NSS results show that the corrosion resistance of the film is dominated by both the film thickness and the cracks.With increasing treatment time,the corrosion resistance of the film increases within 1 h due to the increased film thickness and decreases after 1 h because the cracking and flaking off gradually become dominant factor.展开更多
Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morpholog...Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.展开更多
The transparent PVC films were prepared by tape casting. In the process of prepa ration, rare earth nitrate, as a kind of modifier, was added to th e solution of PVC and THF. These PVC films were tested after being cr...The transparent PVC films were prepared by tape casting. In the process of prepa ration, rare earth nitrate, as a kind of modifier, was added to th e solution of PVC and THF. These PVC films were tested after being crosslinked b y ultraviolet light. It is found that the mechanical and physical properties of all the PVC films modified by rare earth nitrate are greatly enhanced.展开更多
Cerium sulfate was used as main composite in solution to prepare golden yellow chemical conversion film on magnesium alloy. The influence of solution composition on the surface morphology of golden yellow rare earth c...Cerium sulfate was used as main composite in solution to prepare golden yellow chemical conversion film on magnesium alloy. The influence of solution composition on the surface morphology of golden yellow rare earth conversion film on magnesium alloy was studied by means of SEM; potential-time curves in the formation process of rare earth conversion film and the anti-corrosion property of the conversion film were tested through ECT. The results show that, when there is no other component in the solution besides cerium sulfate, yellow film can be obtained on magnesium alloy, but there are some dusts on the film surface and the solution is not stable. The stability of cerium sulfate solution increases with adding hydrogen peroxide, while the film is thin and its color turn light. After adding combination additive containing Al 3+, smooth and compact golden yellow film was obtained on magnesium alloy. The polarization curves tested in 3.5% NaCl solution show that the anti-corrosion property of magnesium alloy is increased obviously by rare earth conversion film, and the film has self-repairing capability in the corrosion process.展开更多
By using surface effects(Auger electron spectroscopy,X-ray photoelectron spectroscopy,polar Kerr effect)and volume effects(magnetization,torque curve)the physical process of surface oxidation of rare earth-transition ...By using surface effects(Auger electron spectroscopy,X-ray photoelectron spectroscopy,polar Kerr effect)and volume effects(magnetization,torque curve)the physical process of surface oxidation of rare earth-transition metal amorphous magneto-optical thin films was studied in this paper.The rare earth elements oxidize preferentially and rich at the film surface,and the transition metals deplete in oxidation layer.Fe_2O_3 in the surface oxidation layer contributes to the planar magnetization,and thereby the anomalous peak appears near 180° on the torque curves and the amplitude of the peaks is related to the depth of surface oxidation layers.The iron bonds to oxygen easier than the cobolt.RE-Co magneto-optieal thin films have good properties of resistance to oxidation and humidity.展开更多
Self-assembled film containing the rare earth (RE) elements was formed on a silicon dioxide substrate, in order to reduce the surface adhesion and the friction force of micro electro-mechanical systems (MEMS). The fil...Self-assembled film containing the rare earth (RE) elements was formed on a silicon dioxide substrate, in order to reduce the surface adhesion and the friction force of micro electro-mechanical systems (MEMS). The film thickness was measured as 2nm. The tribological experiment result shows that the friction coefficient of SiO 2 substrate reduces from 0.5 to 0.1 after the formation of RE self-assembled film on its surface. Besides, RE self-assembled film exhibits a high wear resistant ance.展开更多
Composite nickel hydroxide films were prepared by cathodic co electrodeposition from metal nitrate solution and characterized by cyclic voltammetry in 1.0 mol/L KOH solution. The codeposited light rare earth elements...Composite nickel hydroxide films were prepared by cathodic co electrodeposition from metal nitrate solution and characterized by cyclic voltammetry in 1.0 mol/L KOH solution. The codeposited light rare earth elements were lanthanum, cerium, praseodymium and neodymium. The films were analyzed by spectrophotometry and optical transmission. The results of the cyclic voltammetry in 1.0 mol/L KOH solution showed that the current density for oxygen evolution at the film electrode was affected by the co deposited rare earth metal ions in the film. About 20 mA/cm 2 increase of current density for oxygen evolution was found when the film was obtained from the solution with cerium (7% v/v) and nickel (93% v/v) nitrate. The effects of galvanostatic cathodic current density for the film formation on the oxygen evolution at the film electrodes from the alkaline were discussed.展开更多
Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5 O18)2], K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibila...Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5 O18)2], K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations.展开更多
Ion beam epitaxy （IBE） technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion b...Ion beam epitaxy （IBE） technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion beam epitaxy was reviewed in details. The recent developments and application of IBE on rare-earth functional films is focused, particularly for high-K materials CeO2, photoluminescence materials Gd2O3 and magnetic semiconductor materials Si1-x Gdx.展开更多
The structure, magnetization, and magnetostriction of Sm0.9Pr0.1Fex and Sm1-xNdxFel.9 thin films have been investigated using X-ray diffraction, vibrating sample magnetometer, and optical cantilever method. It is foun...The structure, magnetization, and magnetostriction of Sm0.9Pr0.1Fex and Sm1-xNdxFel.9 thin films have been investigated using X-ray diffraction, vibrating sample magnetometer, and optical cantilever method. It is found that the structure of Sm0.9Pr0.1Fex thin films consists of an Sm-Pr-Fe amorphous phase when x≤2.69 and that of Sm1-xNdxFel.9 thin films consists of an Sm-Nd-Fe amorphous phase. The in-plane magnetization of Sm0.91Pr0.1Fex thin films increases with increase in the Fe content, and low values of the in-plane coercivity occur in the range of 1.62≤ x≤ 2.28. The magnetostriction value of Sm0.91Pr0.1Fex thin films increases with increasing the Fe content when x ≤ 1.94 and decreases when x 〉 1.94. The in-plane magnetostriction of Sm1-xNdxFe1.9 thin films under low magnetic fields has been improved by the substitution of Nd for Sm when x = 0.2.展开更多
The effect of cerium on ignition temperature of AZ91D magnesium alloy was studie d. By the addition of cerium of 1%, the ignition temperature is raised by 180 ℃ , s o the magnesium alloy added with cerium can be melt...The effect of cerium on ignition temperature of AZ91D magnesium alloy was studie d. By the addition of cerium of 1%, the ignition temperature is raised by 180 ℃ , s o the magnesium alloy added with cerium can be melted in air. The burning temper ature increases with the increasing of cerium. The structure and chemical compos itions of the surface oxide film were investigated by XRD and Auger electron spe ctrometry(AES). The results of XRD indicate that the oxide film of the surface o f ignition-inhibition magnesium alloy can change from loose structure of simple magnesia to compact composite structure consisting of magnesia, cerium oxide, M g17 A112 and aluminum oxide, which has excellent ignition-inhibition effect. AE S depth profile analysis shows that the oxide film can be divided into three lay ers. The outside layer is mainly made up of magnesia, the middle layer, which co nsists of cerium oxide, magnesia, and aluminum oxide, is compound and compact. T hermodynamic analysis indicates that the structure of the surface oxide film is accordant to the change of free energy and high vapor pressure of magnesium.展开更多
The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such...The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such as cyclic voltammetry,chronopotentiometry and chronoamperometry were used in order to explore the deposition mechanism of Yb.The reduction process of Yb3+ is stepwise reactions which are single-electron and double-electron reversible charge transfer reactions.The speed control step was a diffu...展开更多
Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scann...Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.展开更多
SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samp...SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samples were measured under the ac applied magnetic field with the period Tp(2πω) , H(t) = H0sin(ωt), by vibrating sample magnetometer (VSM). The experimental results indicate that, (1) the average hysteresis loop areas as functions of the values of H0 andωdisplay a power scaling law with the exponents, A = A0 + H0αωβ; (2) the x composition of SmxCo5 film has evident effect on the scaling behavior and magnetic properties; (3) the anisotropy scaling exponents exist clearly in the anisotropy SmxCo5 thin films. Moreover, the scaling behavior of the anisotropy magnetic film was also simulated with Monte Carlo method. The simulated results are consistent with the experimental fact.展开更多
文摘Hot-dip galvanized(HDG)steel sheets were treated for 30 s?24 h by the rare earth aqueous solution containing 20 g/L Ce(NO3)3·6H2O,and the growth behavior and corrosion resistance of the rare earth film were investigated by SEM,EDS,AES and NSS.The results reveal that the rare earth film becomes thick while the mass gain of the samples does not distinctly change due to the zinc dissolution with the increase of treatment time.The film grows up more quickly and is apt to cracking in the vicinity of zinc grain boundaries,and eventually the film partly warps and flakes off with increasing film thickness.The NSS results show that the corrosion resistance of the film is dominated by both the film thickness and the cracks.With increasing treatment time,the corrosion resistance of the film increases within 1 h due to the increased film thickness and decreases after 1 h because the cracking and flaking off gradually become dominant factor.
基金Project supported by the Science and Technology Foundation of Sci. & Tec. Office of Qinhuangdao City (200507)
文摘Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.
文摘The transparent PVC films were prepared by tape casting. In the process of prepa ration, rare earth nitrate, as a kind of modifier, was added to th e solution of PVC and THF. These PVC films were tested after being crosslinked b y ultraviolet light. It is found that the mechanical and physical properties of all the PVC films modified by rare earth nitrate are greatly enhanced.
文摘Cerium sulfate was used as main composite in solution to prepare golden yellow chemical conversion film on magnesium alloy. The influence of solution composition on the surface morphology of golden yellow rare earth conversion film on magnesium alloy was studied by means of SEM; potential-time curves in the formation process of rare earth conversion film and the anti-corrosion property of the conversion film were tested through ECT. The results show that, when there is no other component in the solution besides cerium sulfate, yellow film can be obtained on magnesium alloy, but there are some dusts on the film surface and the solution is not stable. The stability of cerium sulfate solution increases with adding hydrogen peroxide, while the film is thin and its color turn light. After adding combination additive containing Al 3+, smooth and compact golden yellow film was obtained on magnesium alloy. The polarization curves tested in 3.5% NaCl solution show that the anti-corrosion property of magnesium alloy is increased obviously by rare earth conversion film, and the film has self-repairing capability in the corrosion process.
文摘By using surface effects(Auger electron spectroscopy,X-ray photoelectron spectroscopy,polar Kerr effect)and volume effects(magnetization,torque curve)the physical process of surface oxidation of rare earth-transition metal amorphous magneto-optical thin films was studied in this paper.The rare earth elements oxidize preferentially and rich at the film surface,and the transition metals deplete in oxidation layer.Fe_2O_3 in the surface oxidation layer contributes to the planar magnetization,and thereby the anomalous peak appears near 180° on the torque curves and the amplitude of the peaks is related to the depth of surface oxidation layers.The iron bonds to oxygen easier than the cobolt.RE-Co magneto-optieal thin films have good properties of resistance to oxidation and humidity.
文摘Self-assembled film containing the rare earth (RE) elements was formed on a silicon dioxide substrate, in order to reduce the surface adhesion and the friction force of micro electro-mechanical systems (MEMS). The film thickness was measured as 2nm. The tribological experiment result shows that the friction coefficient of SiO 2 substrate reduces from 0.5 to 0.1 after the formation of RE self-assembled film on its surface. Besides, RE self-assembled film exhibits a high wear resistant ance.
文摘Composite nickel hydroxide films were prepared by cathodic co electrodeposition from metal nitrate solution and characterized by cyclic voltammetry in 1.0 mol/L KOH solution. The codeposited light rare earth elements were lanthanum, cerium, praseodymium and neodymium. The films were analyzed by spectrophotometry and optical transmission. The results of the cyclic voltammetry in 1.0 mol/L KOH solution showed that the current density for oxygen evolution at the film electrode was affected by the co deposited rare earth metal ions in the film. About 20 mA/cm 2 increase of current density for oxygen evolution was found when the film was obtained from the solution with cerium (7% v/v) and nickel (93% v/v) nitrate. The effects of galvanostatic cathodic current density for the film formation on the oxygen evolution at the film electrodes from the alkaline were discussed.
基金supported by the National Nature Science Foundation of China(20071007)the Foundation for University Key Teacher by the Ministry of Education of China
文摘Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5 O18)2], K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations.
文摘Ion beam epitaxy （IBE） technology is a significant method for preparing high pure and high quality rare-earth functional films at low growth temperatue. A new method of preparing rare-earth functional films by ion beam epitaxy was reviewed in details. The recent developments and application of IBE on rare-earth functional films is focused, particularly for high-K materials CeO2, photoluminescence materials Gd2O3 and magnetic semiconductor materials Si1-x Gdx.
基金This study has been supported by the National Natural Science Foundation of China (Nos. 50371025, 50571034) and the Natural Science Foundation of Hebei Province, China (No. 503055)
文摘The structure, magnetization, and magnetostriction of Sm0.9Pr0.1Fex and Sm1-xNdxFel.9 thin films have been investigated using X-ray diffraction, vibrating sample magnetometer, and optical cantilever method. It is found that the structure of Sm0.9Pr0.1Fex thin films consists of an Sm-Pr-Fe amorphous phase when x≤2.69 and that of Sm1-xNdxFel.9 thin films consists of an Sm-Nd-Fe amorphous phase. The in-plane magnetization of Sm0.91Pr0.1Fex thin films increases with increase in the Fe content, and low values of the in-plane coercivity occur in the range of 1.62≤ x≤ 2.28. The magnetostriction value of Sm0.91Pr0.1Fex thin films increases with increasing the Fe content when x ≤ 1.94 and decreases when x 〉 1.94. The in-plane magnetostriction of Sm1-xNdxFe1.9 thin films under low magnetic fields has been improved by the substitution of Nd for Sm when x = 0.2.
文摘The effect of cerium on ignition temperature of AZ91D magnesium alloy was studie d. By the addition of cerium of 1%, the ignition temperature is raised by 180 ℃ , s o the magnesium alloy added with cerium can be melted in air. The burning temper ature increases with the increasing of cerium. The structure and chemical compos itions of the surface oxide film were investigated by XRD and Auger electron spe ctrometry(AES). The results of XRD indicate that the oxide film of the surface o f ignition-inhibition magnesium alloy can change from loose structure of simple magnesia to compact composite structure consisting of magnesia, cerium oxide, M g17 A112 and aluminum oxide, which has excellent ignition-inhibition effect. AE S depth profile analysis shows that the oxide film can be divided into three lay ers. The outside layer is mainly made up of magnesia, the middle layer, which co nsists of cerium oxide, magnesia, and aluminum oxide, is compound and compact. T hermodynamic analysis indicates that the structure of the surface oxide film is accordant to the change of free energy and high vapor pressure of magnesium.
基金supported by 863 Project of Ministry of Science and Technology of China (2006AA03Z510)the National Natural Science Foundation of China (50871033)+1 种基金the Scientific Technology Project of Heilongjiang Province (GC06A212)the fund from Harbin Municipal Science & Technology Bureau (2006PFXXG006)
文摘The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such as cyclic voltammetry,chronopotentiometry and chronoamperometry were used in order to explore the deposition mechanism of Yb.The reduction process of Yb3+ is stepwise reactions which are single-electron and double-electron reversible charge transfer reactions.The speed control step was a diffu...
基金supported by the grants from the Nature Science Foundation of Zhejiang Province (Y406309)Research Program from Science and Technology Bureau of Jinhua City (2008-1-151)
文摘Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.
基金Project supported by the National Key Project for Basic Research of China (20005CB623605)NSF of China ( 10474037)
文摘SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samples were measured under the ac applied magnetic field with the period Tp(2πω) , H(t) = H0sin(ωt), by vibrating sample magnetometer (VSM). The experimental results indicate that, (1) the average hysteresis loop areas as functions of the values of H0 andωdisplay a power scaling law with the exponents, A = A0 + H0αωβ; (2) the x composition of SmxCo5 film has evident effect on the scaling behavior and magnetic properties; (3) the anisotropy scaling exponents exist clearly in the anisotropy SmxCo5 thin films. Moreover, the scaling behavior of the anisotropy magnetic film was also simulated with Monte Carlo method. The simulated results are consistent with the experimental fact.
