Papers by Keyword: Rare Earth (RE)

Abstract: The sustainable development of the rare earth industry is based on the rational allocation of the rare earth resource. This article analyzes the necessity of the regulation control of the rare earth export from the requirements of sustainable development and the current problems of the industry, such as new problems of the quota management in export, intensified trade friction and the increasingly rampant smuggling, and makes feasible proposals to promote the rare earth strategy. China should persist the constructive and responsible attitude, taking the international and national resource and markets into account, pursue a win-win strategy which can not only keep the rare earth supply reasonable in the international market, but also protect the ecological environment and resource.

Abstract: In this paper, the peeling strength between ultra-thin copper foil and carrier is improved by some rare earths used as additives during the formation of the stripping layer of H-G alloy. The effect of different rare earth and their different contents on the stripping property of ultra-thin copper foil with carrier when they are added in the H-G plating solution is investigated, and the influence of rare earth on the cathodic polarization curves and cyclic voltammetry curves of H-G alloy during its electrodeposition is analyzed too. Results show that rare earth elements of La, Sm, Y and Ce increase the peeling strength between ultra-thin copper foil and carrier to a certain extent and the peeling strength is increased from 0.13 kgf •cm-1 to the range of 0.16 ~ 0.20 kgf •cm-1. Different rare earth contents also have impact on the peel strength and surface property of ultra-thin copper foil with a carrier support, in which the optimum adding amount of La is 0.1 g •L-1. Electrochemical test results show that the addition of rare earths can reduce the degree of the plating solution’s polarization, accelerate the electrode reaction speed, increase the alloy reduction capacity, promote alloy’s co-deposition, and improve the bonding strength between alloy layer and substrate, thus the peeling strength between ultra-thin copper foil and carrier is enhanced.

Abstract: In this paper, a new heat stabilizer was prepared, which has shown not only excellence thermal stability, but also shown obvious oxidation resistance and anti-aging properties. This multifunctional heat stabilizer was prepared by organic acid, rare earth and thiourea. The lauric acid as best stuff was chosen from some normal fatty acid and lanthanum nitrate as most potent rare earth was picked up too. Using these raw materials, the best heat stabilizer was synthesized under this conditions of synthesizing at 80°C, reacting 40min, adding 1.0mol/L sodium-hydroxide for keeping PH at 8 and making certain the amount of raw material(lauric acid : thiourea : lanthanum nitrate) at the proportion as 4∶1∶1. The thermal stability was examined by the change time of Congo red, and the result proved this heat stabilizer having good thermal stability for up this time to 40min. When this rare earth stabilizer was joined into PVC, the PVC can keep its color not changing during 48h under ultraviolet radiation, and the tensile strength and elongation at break of the PVC added rare stabilizer changed more little under ultraviolet radiation compared with the traditional heat stabilizer system. So this rare earth heat stabilizer acting as a good heat stabilizer, anti-oxidant and anti-aging agent is a new multifunctional heat stabilizer.

Abstract: The original austenite grain size, the inclusions and the isothermal annealing microstructure of 20MnCrNi2Mo wear-resistant cast steel without and with Rare Earth were observed by metallographic microscope and QUANTA-400 environmental scanning electronic microscope. The effect mechanism of Rare Earth in 20MnCrNi2Mo wear-resistant cast steel was investigated. The results show that adding Rare Earth in 20MnCrNi2Mo wear-resistant cast steel can refine the original austenite grains. Meanwhile, it can reduce the inclusions size and change the inclusions shape from irregular to nearly spherical. In addition, the Rare Earth in 20MnCrNi2Mo wear-resistant cast steel can increase the amount of ferrite, reduce that of pearlite in the isothermal annealing microstructure and refine the microstructure of pearlite.

Abstract: Drought is a most serious hazard to life and property. In arid and semi-arid region，we must make rational use of the short water resources , and use all sorts of drought resistant material to improve water use efficiency, so scientifically solve the water environment problem of the plant. This paper proposes the use of super absorbent polymers and drought resistant material to improve the arid region of environmental problems. And the traditional probability statistical method is acceptable in analyzing the drought risk but requires a large sample size of hydrological data. This paper also puts forward an improved method based on information diffusion method for drought analysis. Information diffusion theory helps to extract as much useful information as possible from the sample and thus improves the accuracy of system recognition. Furthermore, information diffusion theory helps to extract as much useful information as possible from the sample and thus improves the accuracy of system recognition. This technique contributes to a reasonable prediction of natural disasters risk.

Abstract: Thirteen novel complexeswere synthesized using this method, by employing the designed ligand o-carboxylbenzaldehyde-2-pyrroleformylhydrazone (H₂L). Elemental analysis, molar conductivity,Fourier transform infrared (FTIR) spectracharacterizations show that the composition formula of the complexes is RE(HL)(H₂L)•2H2O (where RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb and Y). The thermal decomposition of the thirteen complexes was studied by _{Subscript text}TG-DTG analysis and their apparent activation energies (E) were calculated by Kissinger’s and Flynn-Wall-Ozawa’s methods.

Abstract: The corrosion process of rare earth (RE) SPCC steel and SPCC steel in CSP in 3.5% NaCl solutions was investigated by SEM, EDS, XRD and polarization curve measurements. The results show that grain refinement can be obtained, the inclusions will be formed, and the electrochemical corrosion of microscopic region is weakened and therefore the corrosion resistance of SPCC steel could be improved by addition of RE. The rust layer of RE treated steel generated in the solution is more compact, the α-FeOOH content in rust layer is higher, and the content of activated γ-FeOOH and β-FeOOH is smaller, which are helpful to protect the steel. It also shows that current densities of SPCC steel is lower and the corrosive tendency will decrease with the addition of RE, which also makes the corrosion resistance of steel improved.

Abstract: Solidification behavior of LaFe_13-xSi_x alloys was investigated using rapidly quenching and. Phase formation and structure in rapidly quenched LaFe_13-xSi_x alloys has been investigated by means of power X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results have shown that 1:13 phase is a peritectic phase. The solidification behavior of LaFe13-xSix alloys depend on x, cooling rate. Under small undercooling, the 1:13 phase is difficult to formed with x=0.5 to 3.0. The α-(Fe,Si) phase and the 1:2:2 phase is mainly phase in the microstructure of alloy with low and high Si contents, respectively. Under higher cooling rate, the microstructure of compositions with x≥1.5 occurs the 1:13 phase. The α-(Fe,Si) phase and the 1:13 phase is mainly phase in the microstructure of alloy with low and high Si contents, respectively. The microstructure of compositions with x=2.5 to 3.0 are mainly phase which is primary phase. The results were discussed with respect to the effect of cooling rate.

Abstract: Cast performance study of 8Cr4MoV cold work roll steels with four kinds of different rare earth content was carried out in the laboratory, the steels smelting by 50kg vacuum induction furnace, atmospheric casting, processing sample after annealing, then inspecting the microstructure, mechanical properties and micro-fracture characteristics of the steels; The results showed that the steels’ microstructure fine, micro-hardness and tensile strength increased with increasing rare earth content, while the shrinkage to eliminate, the micro-fracture characteristics of the tensile specimen showed a tendency of the cleavage unit narrowing and reduction of secondary cracks, and also the ductility improved.

Abstract: Erbium doped borotellurite glass has been identified as one of the most potential candidate for optical applications due to their excellent in physical and chemical properties. Therefore, the aim of this study is to identify the optical properties by mean of their UV-Vis and photoluminescence spectroscopic of the Er³⁺ doped borotellurite glass. In this work, erbium doped borotellurite glass, (80-x)TeO₂-10 B₂ O₃-10PbO-xEr₂O₃, where 0.5 mol % x 2.0 mol % has been successfully fabricated by using melt-quenched techniques. The glass obtained is in good quality since it shows no sign of devitrification. The glass sample has undergone some physical and optical measurements. From the XRD results, it confirms that the glass is in amorphous nature. Meanwhile, it is found that the density of the glass sample increases from 4.4187 gcm^-3 to 4.5769 gcm^-3 with respect to Er content. For the optical properties, the absorption spectra were measured by UV-Vis-NIR spectrophotometer in the range 400-900 nm interval. From the absorption spectra, the 650 nm excitation wavelength is found to be the most predominant peaks. From the photoluminescence spectra, five significant emission peaks have been observed where by four of them is in the visible regions which is corresponds to 440 nm, 486 nm, 520 nm and 650 nm wavelength while the other one is in NIR regions at 794 nm. Some other results were also been analyzed and presented.