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Yu Y.,State Key Laboratory Of Nonferrous Metals And Processesgeneral Research Institute For Nonferrous Metalsbeijing 100088Pr China | Zhang J.,GRIPM Advanced Materials Co. | Xiao W.,China Institute of Technology | Wang J.,State Key Laboratory Of Nonferrous Metals And Processesgeneral Research Institute For Nonferrous Metalsbeijing 100088Pr China
Physica Status Solidi (B) Basic Research | Year: 2017

Segregation at metal alloy surfaces has an important impact on their catalytic and chemical properties. We have performed density-functional theory calculations to investigate the surface segregation behaviors of Ni3M (M=Mo, Co, Fe) alloys in the presence of chemisorbed atomic oxygen. The calculated results show that the segregation trend at a Ni3M(111) surface can be substantially modified by reactive gaseous environments. At an oxygen coverage of 1/4 ML, both the Ni-segregated and M-segregated surfaces are still less stable than the nonsegregated one for Ni3Fe alloy, while an M-segregated surface is more stable than the nonsegregated one for Ni3M (M=Mo, Co) alloys. Furthermore, the analysis of oxygen adsorption trends and surface electronic structures explains that the surface segregation trend is directly correlated to the surface-adsorbate binding strength. The present study provides valuable insight for exploring practical applications of Ni-based alloys as hydrogen-evolution electrodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Qi H.,General Research Institute for Nonferrous Metals, China | Wang L.,General Research Institute for Nonferrous Metals, China | Wang L.,GRIPM Advanced Materials Co. | Wang L.,Beijing Hengyuantianqiao Powder Metallurgy Co. | And 6 more authors.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2017

Three-dimensional finite element simulation method was applied to establish the model of composite cam for interference assembling process. The equivalent stress distribution of composite cam in the assembling process was analyzed. The effects of inlayer thickness and material of inlayer on assembly stress of composite cam were discussed. Meanwhile, the experiment of assembly was performed to validate the model. Compared with 45# steel inlayer material for composite cam, powder metallurgy (Fe-Cu-C) material can preferably ease stress in the assembly process. When the magnitude of interference between the cam and tube is 0.08 mm, the surface stress for powder metallurgy (Fe-Cu-C) inlayer material is 38% of that for 45# steel inlayer material, and the result is 40% through experimental verification. It turns to be roughly accordant for data between simulation and experiment with its error of 5%. By using the model, optimization design of layer structure is processed on different thickness and the allowed thicknesses for inlayer rang from 1.75 to 2.25 mm, and the optimized thickness is 2.05 mm. © 2017, Editorial Office of Materials Science and Engineering of Powder Metallurgy. All right reserved.


Liu Y.,Beijing Gang Yan Diamond Products Company | Wang L.,GRIPM Advanced Materials Co. | Wang L.,CompuTherm LLC | Zhang C.,CompuTherm LLC
Advanced Materials Research | Year: 2013

Rare earth silicates (RE2SiO5 or RE2Si2O7; RE=Er, Lu, Y, Yb etc.) possess a low silica activity and good thermal stability, making them good candidates for EBC top coating materials. We have performed first-principles total energy calculations for the Er2O3-SiO2 pseudo binary system. The crystal lattice parameters and internal atomic coordinates of Er2SiO5 and Er2Si2O7 are optimized, and the electronic structure and formation enthalpies are calculated. The present study provides a theoretical basis for exploring practical applications of the materials. © (2013) Trans Tech Publications, Switzerland.


Wang Z.,Beijing University of Technology | Liu F.,Beijing University of Technology | Liu F.,GRIPM Advanced Materials Co. | He D.,Beijing University of Technology | Tian L.,Beijing University of Technology
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2016

The Fe-Nb-C-B-Ni-WC (30%) iron-based tungsten carbide wear resistant hardfacing alloy was deposited on the Q235 byargontungsten-arcwelding (TIG) using flux-cored wire. The effect of niobium content on the dissolution of tungsten carbide in the alloy was studied by changing the niobium content from 1.0% to 3.8%. The results show that niobium content has a great influence on the degree of dissolution of tungsten carbide in the alloy. The primarily precipitated fine NbC particles around the tungsten carbide inhibit the dissolution of tungsten carbide. The amount of fine NbC determines the intensity of the inhibitory effect on the dissolution of tungsten carbide. The alloy with 2.5% niobium effectively inhibit the dissolution of tungsten carbide in the alloy, the original tungsten carbide particles were reserved more completely. © 2016, Harbin Research Institute of Welding. All right reserved.


Yang Z.,University of Science and Technology Beijing | Yang Z.,Gripm Advanced Materials Co. | He X.,University of Science and Technology Beijing | Wang L.,Gripm Advanced Materials Co. | And 3 more authors.
Journal of the European Ceramic Society | Year: 2014

Diamond/SiC/(Si) composites were fabricated by Si vapor vacuum reactive infiltration. The coefficient of thermal expansion (CTE) of composites have been measured from 50 to 400. °C. With the diamond content increasing, CTE of composite decreased, simultaneously, the microstructure of the composites changed from core-shell particles embedded in the Si matrix to an interpenetrating network with the matrix. The CTEs of composites versus temperature matched well with those of Si. The Kerner model was modified according to the structural features of the composites, which exhibited more accurate predictions due to considering the core-shell structure of the composites. The thermal expansion behavior of the matrix was constrained by diamond/SiC network during heating. © 2013 Elsevier Ltd.


Patent
General Research Institute for Nonferrous Metals, China, Beijing Hengyuan Tianqiao Power Metallurgy Co. and Gripm Advanced Materials Co. | Date: 2012-09-28

According to the invention, there are disclosed a power metallurgy composite cam sheet and a fabrication method thereof. The power metallurgy composite cam sheet is constructed by combining a power metallurgy cam be composited on a surface of a matrix. The fabrication method of the power metallurgy composite cam sheet includes sinter welding, braze welding, argon arc welding, laser welding, hot pressing and other methods. The powder metallurgy composite cam sheet fabricated by the invention has merits of stable size, good impact toughness, good abrasion resistance, low cost and so on, so that it can replace an integral cam sheet that is currently fabricated by forging, drawing, power metallurgy or other process. It is suitable for the case where a hollow camshaft is prepared by mechanical assembly, hydraulic forming, welding or other process, so that the usage requirements of an assembled camshaft can be met.


Wang L.,General Research Institute for Nonferrous Metals, China | Wang L.,GRIPM Advanced Materials Co. | Zhang G.,General Research Institute for Nonferrous Metals, China | Ma F.,General Research Institute for Nonferrous Metals, China | Ma F.,GRIPM Advanced Materials Co.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2010

In order to retrieve the valuable metals in waste diamond tools, potential-pH diagrams of five common valuable metals (nickel, iron, copper, cobalt, tin) in diamond tools were drawn by means of consulting thermodynamic data and analyzed. By analysis, these five elements could be leached by adopting mixed acid composed of hydrochloric acid and nitric acid, which was verified by experiments. The results showed that the leaching rates of various metals were about 99% when the condition was the weight of the diamond tool of 21. 44 g (Cu: 35%, Fe: 20%, Ni: 15%, Co: 15%, Sn: 15%), total acid (volume ratio of hydrochloric acid:nitric acid=3:2) of 140 ml, the constant temperature water bath for leaching system was heated to 96°C, stirring speed of 500 r·min-1 and the reaction time of 80 min for efficient extraction.


Zhang J.,GRIPM Advanced Materials Co. | Wang L.,GRIPM Advanced Materials Co.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2011

The Cu/Fe composite powders with copper of 20% as the core of Fe particles were synthesized by substitution reaction, with organic acids as addition agent, with acidic and alkaline waste cupric liquor and reduced iron powders. The influences of the Cu2+ concentration, the reaction time, and the drying and reduction process on the property of powders were investigated by flame atomic absorption spectrometry, inert gas fusion-thermal conductivity, X-ray diffraction and scanning electron microscope. The Cu/Fe composite powders were also dealt by vacuum heating-press sintering. The results showed that the Cu/Fe composite powders had the microstructure that Fe particle was coated with Cu coating, and the thickness of which was about 1 μm. The solutions with higher the Cu2+ concentration had faster reaction rate. The reaction time ranged from 25 to 30 min. It was better for the drying and reduction process that the reduction temperature was between 500 and 650 °C, and the reduction time was between 2 and 3 h. The Cu/Fe composite powders were made of Cu phase and Fe phase. Under the same temperatures, HRB hardness and anti-bending hardness of sintered specimens of the composite powders passing through ≤74 μm sieve were higher than that of the powders passing through ≤150 μm sieve. The better temperature for hot press performance was between 700 and 750 °C.


Zhang J.,GRIPM Advanced Materials Co. | Zhang J.,General Research Institute for Nonferrous Metals, China | Wang L.,GRIPM Advanced Materials Co. | Wang L.,General Research Institute for Nonferrous Metals, China
Advances in Powder Metallurgy and Particulate Materials - 2010, Proceedings of the 2010 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2010 | Year: 2010

To better understand the formation mechanism of electrolytic copper powder with dendritic shape, we have carried out a characterization of the morphology evolution process at the microscale. In particular, the morphology of electrolytic copper powder with different concentrations of copper ion in the electrolyte is examined respectively. Our findings show that there are three periods in the morphology evolution process. The morphology of single needle dendritic shape is first observed with lower concentration of copper ion of 2.50~4.98g/dm3. With the increasing of concentration of copper ion to 6.74 g/dm3, the morphology of single needle dendrites is converted to the morphology of multi-dendritic shape. When the higher concentration of copper ion of 11.04 g/dm3 is presented, the morphology has thoroughly changed compared to the above reports and becomes sponge shape. The formation mechanism of electrolytic copper powder which is controlled by concentration of copper ions in the electrolyte and effective current density is also discussed in the paper. © 2010 Metal Powder Industries Federation.


Zhang J.,General Research Institute for Nonferrous Metals, China | Zhang J.,GRIPM Advanced Materials Co. | Zhang S.,General Research Institute for Nonferrous Metals, China | Wang L.,General Research Institute for Nonferrous Metals, China | Wang L.,GRIPM Advanced Materials Co.
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

The current situation anddevelopment of copper and copper alloy powders in China and abroad in recent years were introduced in this paper. The gap with the advanced countries in the world and existing problems, such as production technology, equipment and market etc, were analyzed. Some suggestions for further development were put forward.

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