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Hydrogen permeation resistance and characterization of Si–Al and Si–Zr composite sol oxide coating on surface of zirconium hydride

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rare metals 2017年第1期36卷 55-60页

作者： Ming Wu Yang Chen Jia-Qing Peng Guo-Qing Yan Yu-Pu Sun Jian-Dong Zhang Shun-Li Zhang Li-Jun Wang Division of rare metals Metallurgy and Materials General Research Institute for Nonferrous Metals Beijing 100088 China

The hydrogen permeation resistance of Si–Zr(SZ) and Si–Al(SA) composite sol oxide coating on zirconium hydride blocks(Zr H) was studied. SZ and SA composite sol were prepared by sol–gel method. SZ and SA composite oxide coatings were prepared on the surface of Zr H(in situ oxidized or not) in turns by dip-coating and heat treatment. Hydrogen permeation of Zr Hwith and without composite oxide coating was *** desorption experiments in thermal vacuum show that hydrogen permeation resistance of SA composite oxide coating is better than that of SZ, to a certain extent,which could decrease hydrogen thermal loss. Experimental results in the working condition show that the SA composite oxide coating can not only prevent hydrogen permeation, but also retard contact and reaction between COand Zr Hmatrix, which could mitigate excessive oxidation of in situ oxide film. Differential scanning calorimetry and thermogravimetry(DSC–TG) analysis was performed to investigate the decomposition behavior of SA and SZ liquid sol in heat treatment process. X-ray diffraction(XRD) and scanning electron microscopy(SEM) analysis were employed to characterize the phase composition,surface and cross-section morphology of the coatings.

关键词： Zirconium hydride Hydrogen permeation resistance Composite oxide coating Si–Zr Si–Al Sol–gel

Magnetic properties optimization of nanocomposite Nd_9Fe_(85)B_6 magnets by controlling microstructure of as-quenched ribbons

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rare metals 2014年第3期33卷 299-303页

作者： Yu-Chao Liu Hong-Wei Li Kuo-She Li Dun-Bo Yu Jin-Ling Jin Yang Luo Liang Sun Ning-Tao Quan National Engineering research Center for rare earth Materials General Research Institute for Nonferrous Metals

To optimize the magnetic properties of nanocomposite Nd9Fe85B6 magnets, the as-quenched ribbons with different microstructures were prepared at six wheel velocities from 10 to 30 m s^-1through rapid quenching,followed by a series of annealing treatments at 550-800 °C for 5-10 min. It is found that both the large initial grains at low cooling rate and high content of amorphous phase at high cooling rate cause a-Fe grains coarsening, which leads to a decline in the strength of exchange coupling interaction and the deterioration of magnetic properties. In order to optimize the magnetic properties, the as-quenched ribbons should be chosen with relatively small initial grains as well as a small amount of amorphous phase. For nanocomposite Nd9Fe85B6 materials, the optimized magnetic properties of Hcj= 446 kA m^-1, Br= 0.86 T,（BH）max=80 kJ m^-3are obtained for ribbons prepared at 18 m s-1after annealing at 620 °C for 5 min.

关键词： Nanocomposite Rapid quenching Microstructure Grain sizes

Effect of thermal shield and gas flow on thermal elastic stresses in 300mm silicon crystal

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rare metals 2006年第Z2期25卷 45-50页

作者： GAO Yu XIAO Qinghua ZHOU Qigang DAI Xiaolin TU Hailing General research institute for nonferrous metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China

The thermal elastic stresses induced in 300 mm Si crystal may be great troubles because it can incur the generation of dislocations and undesirable excessive residual stresses. A special thermal modeling tool, CrysVUn, was used for numerical analysis of thermal elastic stresses and stress distribution of 300 mm Si crystal under the consideration of different thermal shields and gas flow conditions. The adopted governing partial equations for stress calculation are Cauchy′s first and second laws of motion. It is demonstrated that the presence and shape of thermal shield, the gas pressure and velocity can strongly affect von Mises stress distribution in Si crystal. With steep-wall shield, however, the maximal stress and ratio of high stress area are relatively low. With slope-wall shield or without shield, both maximal stress and ratio of high stress area are increased in evidence. Whether thermal shields are used or not, the increase of gas flow velocity could raise the stress level. In contrast, the increase of gas pressure cannot result in so significant effect. The influence of thermal shield and gas flow should be attributed to the modification of heat conduction and heat radiation by them.

关键词： thermal elastic stress simulation 300 mm Si single crystal

Electrolytic properties and element migration in Ni-TiB_(2)/Al_(2)O_(3)composite cathode

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rare metals 2021年第1期40卷 57-64页

作者： Yu-Dong Liang Li-Jun Wang Deng-Peng Chai Sheng-Zhong Bao Ting-Ting Niu Jun-Wei Wang Ying Liu rare metals and Metallurgy Materials research institute General Research Institute for Nonferrous MetalsBeijing 100088China Zhengzhou nonferrous metals research institute Co. LtdChaleoZhengzhou 450041China

With alumina sol as binder and Ni metal as sintering aids,the Ni-TiB_(2)/Al_(2)O_(3) composite cathode material for aluminum electrolysis was prepared by coldpressed *** mechanical properties of the composite cathode material were *** electrolytic properties were identified by a 20-A electrolysis *** samples before and after electrolysis test were measured by energy-dispersive spectroscopy(EDS).The migration behavior of various elements in the electrolysis process was studied by phase *** result shows that Ni metal can effectively fill the gap between the aggregate during the sintering process,which can improve the sintering density of the composite cathode material *** voltage of the 20-A electrolysis test is *** impurity of aluminum liquid is 0.42%.The aluminum liquid can wet the cathode surface effectively,and the Ni-TiB_(2)/Al_(2)O_(3) composite is an ideal wettable cathode *** the process of electrolysis,the alkali elements in the electrolyte penetrate the electrode,where K goes deeper than *** generated on the cathode surface will also penetrate the cathode through the gap of the composite material,while Ni in the electrode will spread into the aluminum liquid layer.

关键词： Aluminum electrolysis TiB_(2) Alumina sol Cold-pressed sintering Infiltration

Recovery of copper and tin from stripping tin solution by electrodeposition

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rare metals 2014年第3期33卷 353-357页

作者： Bin Li De-An Pan Yu-Hui Jiang Jian-Jun Tian Shen-Gen Zhang Kun Zhang institute for Advanced Materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing beijing nonferrous metals and rare earth research institute

In this paper, the method of recycling copper and tin by constant-current and constant-voltage electrolysis from the stripping tin solution of tinned copper wastes was studied. The experimental results show that the elements could be deposited on the cathode in turn by different deposition potentials, therefore, the copper and tin were separated by constant-voltage electrolysis but not constant-current electrolysis. In this study, the influence of anode materials was also investigated. Graphite anode is stable without impurities dissolved into the stripping tin solution, while 316 stainless steel anode is dissolved into Fe2？and Fe3？as anodic corrosion, which could decrease the deposition efficiency of tin. The copper and tin in the stripping tin solution are separated orderly by electrodeposition at different voltages using the graphite anode. The recovery rate of copper is up to 100 % at 2.00 V, while that of tin is 80 % at 3.00 V.

关键词： Electrodeposition Copper Tin Stripping tinsolution

Preparation of pure SnO_2 powders from tin slag of printed circuit boards waste

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rare metals 2014年第6期33卷 749-753页

作者： Bin Li Shen-Gen Zhang Kun Zhang De-An Pan Jian-Jun Tian Duan-Ting Zhang institute for Advanced Materials and Technology School of Materials Science and Engineering University of Science and Technology Beijing beijing nonferrous metals and rare earth research institute

The recycling method and principle of SnO2 from the tin slag of printed circuit boards（PCB） waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size（D50）. This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.

关键词： SnO2 Tin slag Printed circuit boards(PCB) waste

Ce_(1–x)La_xO_y solid solution prepared from mixed rare earth chloride for soot oxidation

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Journal of rare earths 2016年第6期34卷 590-596页

作者：韩雪王亚飞郝红蕊郭荣贵胡运生蒋文全 institute of rare earth Metallurgical Materials General Research Institute for Nonferrous MetalsBeijing 100088China School of Mechanical Engi-neering Beijing Institute of Petrochemical TechnologyBeijing 102617China

Ce_（1–x）La_xO_y solid solution was simply prepared using mixed rare earth chloride（RECl_3·x H_2O, RE=Ce, La99%, containing unseparated Ce and La from rare earth metallurgical industry） as precursor by ultrasonic-assisted co-precipitation method with different ultrasonic frequencies（CLf, f=200, 400, 600, 800, 1000 Hz）. A compared Ce_（1–x）La_xO_y solid solution（CL＊） was also prepared by the same mothod with 10% less precipitant. X-ray diffraction results confirmed the formation of Ce1–xLaxOy solid solution, and the crystal structures of these catalysts were not very sensitive to ultrasonic frequency and precipitant amount. However, both of the factors had obvious effect on morphology and surface area of CL, and precipitant amount seem to play a more crucial role than ultrasonic frequency for Ce_（1–x）La_xO_y solid solution preparation. When soot and catalyst were tight contacted, the peak temperature（Tpeak） of soot oxidation and oxygen reducing temperature for CLf catalysts decreased linearly with increasing surface area. Under loose contact condition, the Tpeak had obvious negative correlation with H_2 consumption. It was inferred that good reducibility of the Ce_（1–x）La_xO_y solid solution favored the soot oxidation reaction. The Ce_（1–x）La_xO_y solid solution prepared from unseparated rare earth chloride showed a good soot oxidaiton activity. Controlling the preparation conditions to prepare a CL catalyst would high surface area will enhance its reducibility and activity.

关键词： Ce_(1–x)La_xO_y solid solution soot oxidation mixed rare earth chloride ultrasonic-assisted method co-precipitation

Nucleation mechanisms of dynamic recrystallization in Inconel 625 superalloy deformed with different strain rates

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rare metals 2012年第3期31卷 215-220页

作者： Guo, Qingmiao Li, Defu Peng, Haijian Guo, Shengli Hu, Jie Du, Peng nonferrous metals Processing Division General Research Institute for Nonferrous Metals Beijing 100088 China

The effects of strain rates on the hot working characteristics and nucleation mechanisms of dynamic recrystallization (DRX) were studied by optical microscopy and electron backscatter diffraction (EBSD) technique. Hot compression tests were conducted using a Gleeble-1500 simulator at a true strain of 0.7 in the temperature range of 1000 to 1150 °C and strain rate range of 0.01 to 10.00 s?1. It is found that the size and volume fraction of the DRX grains in hot-deformed Inconel 625 superalloy firstly decrease and then increase with increasing strain rate. Meanwhile, the nucleation mechanism of DRX is closely related to the deformation strain rate due to the deformation thermal effect. The discontinuous DRX (DDRX) with bulging of original grain boundaries is the primary nucleation mechanism of DRX, while the continuous DRX (CDRX) with progressive subgrain rotation acts as a secondary nucleation mechanism. The twinning formation can activate the nucleation of DRX. The effects of bulging of original grain boundaries and twinning formation are firstly gradually weakened and then strengthened with the increasing strain rate due to the deformation thermal effect. On the contrary, the effect of subgrain rotation is firstly gradually strengthened and then weakened with the increasing strain rate.

关键词： nucleation mechanisms dynamic recrystallization Inconel 625 superalloy deformation strain rate

Microstructure and thermal conductivity of copper matrix composites reinforced with mixtures of diamond and SiC particles

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rare metals 2012年第1期31卷 58-63页

作者： Han, Yuanyuan Guo, Hong Yin, Fazhang Zhang, Ximin Chu, Ke Fan, Yeming nonferrous metals Processing Division General Research Institute for Nonferrous Metals Beijing 100088 China

The thermal conductivity of diamond hybrid SiC/Cu,diamond/Cu and SiC/Cu composite were calculated by using the extended differential effective medium (DEM) theoretical model in this *** effects of the particle volume fraction,the particle size and the volume ratio of the diamond particles to the total particles on the thermal conductivity of the composite were *** DEM theoretical calculation results show that,for the diamond hybrid SiC/Cu composite,when the particle volume fraction is above 46% and the volume ratio of the diamond particles to the SiC particles is above 13:12,the thermal conductivity of the composite can reach 500 W·m-1·*** thermal conduc-tivity of the composite has little change when the particle size is above 200μ*** experimental results show that Ti can improve the wettability of the SiC and *** thermal conductivity of the diamond hybrid SiCTi/Cu is almost two times better than that of the diamond hybrid SiC/*** is feasible to predict the thermal conductivity of the composite by DEM theoretical model.

关键词： diamond hybrid SiC/Cu composite microstructure thermal conductivity differential effective medium