检索结果-南通市图书馆

Kinetics of hydrogen absorption and desorption of a mechanically milled MgH_2+5at%V nanocomposite

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2006年第4期13卷 359-362页

作者： Qian Li Kuangdi Xu kuochih chou Xionggang Lu Qin Lin School of Materials Science and Engineering Shanghai University Shanghai 200072 China Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China

The experimental data in the MgH2-5at%V composite was summarized and used to investigate the kinetic mechanism of hydrogen absorption and desorption using a new model. The research results indicate that a coincidence of the theoretical calculation values with the experimental data has been reached and the rate-limiting step is hydrogen diffusion through the hydride phase （β phase） with the activation energy of 47.2 kJ per mole H2 for absorption and the diffusion of hydrogen in the a solid solution （α phase） with that of 59.1 kJ per mole H2 for desorption. In addition, the hydriding rate of the MgH2-V composite is 2.9 times faster than that of MgH2 powders when compared with their characteristic absorption time directly.

关键词： hydrogen-containing alloys magnesium-based alloy kinetics models activation energy

Effects of PVP on the preparation and growth mechanism of monodispersed Ni nanoparticles

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2008年第6期27卷 642-647页

作者： LIU Xiaodan GUO Min ZHANG Mei WANG Xidong GUO Xiao chou kuochih Department of Physical Chemistry University of Science and Technology Beijing Beijing 100083 China College of Engineering Peking University Beijing 100871 China

Monodispersed Ni nanoparticles were successfully prepared by chemical reduction with hydrazine hydrate in ethylene glycol. The effect of the amount of polyvinylpyrrolidone （PVP-K30） on the preparation of Ni nanoparticles was investigated. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and high resolution transmission electron microscopy （HRTEM） were employed to characterize the nickel powders. The average nickel particle size can be controlled from 103 nm to 46 ran with increasing the mass ratio of PVP to NiCl2·6H2O. The particles are spherical in shape and are not agglomerated. A possible extensive mechanism of nickel nanoparticle formation has been suggested.

关键词： Ni nanoparticles nucleation mechanism chemical reduction PVP

Thermodynamics and kinetics of phase transformation in rare earth–magnesium alloys:A critical review

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第9期44卷 171-190页

作者： Qun Luo Yanlin Guo Bin Liu Yujun Feng Jieyu Zhang Qian Li kuochih chou Materials Genome Institute&State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy&Laboratory for Microstructures&Institute of Materials&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

Magnesium and its alloys are significant superior metallic materials for structural components in automobile and aerospace industries due to their excellent physicomechanical *** Mg–rare earth(RE)systems have attracted great interests because RE additions can improve both the deformability and the strength of Mg alloys through solid solution strengthening and precipitation hardening *** paper focuses on the interface stability,together with thermodynamics and kinetics of nucleation and growth of the key phases and matrix phases in Mg–RE *** this paper,the theory and recent advances on Mg–RE alloys,especially for the interface stability,thermodynamics and kinetics of nucleation and growth of the key phases and matrix phases,together with their relationships with micro-structures,and macroscopic properties,are *** combining the thermodynamics/kinetics integrated simulations with various advanced experimental techniques,“reverse”design of Mg–RE alloys starting from the target service performance is put forward as a kind of scientific paradigm with rational design.

关键词： Rare earth–magnesium alloys Thermodynamics Kinetics Phase Properties

New formulae for calculating activities from binary system phase diagrams containing solid solution by introducing the parameterθ

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1997年第3期11卷 1-4页

作者： ZHANG Fan XIE Fanyou CAI Wenjuan chou kuochih (Applied Science School, University of Science and Technology Beijing, Beijing 100083, China)

New formulae for calculating activities and activity coefficients from binary phase diagrams containing solidsolution are presented. In the new formulae, a parameterθ is introduced. It seems be more efficient The app... 详细信息

关键词： phase diagram activity activity coefficient solution θ parameter

Effect of cerium on the cleanliness of spring steel used in fastener of high-speed railway

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第8期32卷 759-766页

作者：刘延强王丽君周国治 State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Department of Physical Chemistry School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investigated by metallographic examination, SEM-EDS and composition analysis. The results indicated that the contents of oxygen decreased with the addition of Ce （[Ce]〈0.1%） and the content of sulfur continually decreased with increasing content of Ce （[Ce]〈1.2%）. However, with the further increase of Ce element addition, the content of [O] and T[O] began to increase. The content of Ce corresponding to the lowest [O] and T[O] lied in the range of 0.10%-0.13%and 0.045%-0.065%, respectively. The addition of Ce in spring steel resulted in the formation of rare earth oxides/oxysulfides and decreased the size of inclusions to less than 3μm in globular or spheroid shape. Moreover, the residual harmful elements （As, P, Pb and Sn） were found to exist in the Ce-containing inclusions, which had proved that the Ce addition could capture the residual elements and suppress their precipitation behaviors in the grain boundary.

关键词： cerium inclusions residual elements spring steel high-speed railway rare earths

Leaching of Carbothermic Reduced Titanium-bearing Blast Furnace Slag by Acid

在线全文

学校读者我要写书评

暂无评论

Journal of the Chinese Ceramic Society 2016年第1期3卷 1-8页

作者： ZHEN Yulan ZHANG Guohua chou kuochih State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

The kinetics of the leaching of carbothermic reduced titanium-bearing blast furnace slag in Panzhihua Iron and Steel Company with acid system under atmosphere pressure was studied. The results show that the temperature and concentration have significant influence on leaching of carbothermic reduced titanium-bearing blast furnace slag by acid. The experimental data of leaching indicate that the shrinking core model with chemical reaction controlled process is most applicable for the acid leaching. The apparent activation energy can be estimated to be from 23 to 32 k J/mol. Furthermore, the main products are TiC and SiO_2 after leaching.

关键词： titanium-bearing blast furnace leaching kinetics

磁场辅助烧结法制备La_(0.67)Mg_(0.33)Ni_3储氢合金

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2013年第2期42卷 392-395页

作者：刘静李谦周国治贵州师范大学贵州贵阳550001 上海大学上海200072

采用磁场辅助烧结合成法(MASS)制备了化学计量比为La_(0.67)Mg_(0.33)Ni_3的储氢合金,通过X射线衍射(XRD)、等温定容法(PCT)和差示扫描量热法(DSC)分析了合金的相结构和吸放氢性能。XRD结果显示:合金主相为PuNi3型结构的(La,Mg)Ni3,氢... 详细信息

采用磁场辅助烧结合成法(MASS)制备了化学计量比为La_(0.67)Mg_(0.33)Ni_3的储氢合金,通过X射线衍射(XRD)、等温定容法(PCT)和差示扫描量热法(DSC)分析了合金的相结构和吸放氢性能。XRD结果显示:合金主相为PuNi3型结构的(La,Mg)Ni3,氢化后分解为以La2Ni7、MgNi2和LaNi3结构为主的复相产物,合金因吸氢发生晶格膨胀。PCT测试表明:1T磁场下合成的合金在室温下具有最小的滞后系数(0.480)、最大的放氢量1.307(质量分数,%),综合性能最优。该合金放氢DSC曲线上有2个交叠的吸热峰,分别对应于(La,Mg)Ni3和LaNi5氢化后的放氢过程。

关键词：磁场辅助烧结储氢合金吸放氢性能

在线全文

学校读者我要写书评

暂无评论

短路还原法提取铁的研究

金属学报 2006年第1期42卷 87-92页

作者：高运明郭兴敏周国治武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室武汉430081 北京科技大学冶金与生态工程学院北京100083

采用氧离子导体氧化锆管与还原剂碳、含有电活性物质 FeO 的熔渣组成电化学体系,利用原电池短路方法从氧化物熔渣中电化学还原得到了无碳金属．实验电池组成为：石墨,[O]_(Fe-C(saturated))|ZrO_2(MgO)|Cu_((1))+(FeO)_((slag)),钼丝．... 详细信息

采用氧离子导体氧化锆管与还原剂碳、含有电活性物质 FeO 的熔渣组成电化学体系,利用原电池短路方法从氧化物熔渣中电化学还原得到了无碳金属．实验电池组成为：石墨,[O]_(Fe-C(saturated))|ZrO_2(MgO)|Cu_((1))+(FeO)_((slag)),钼丝．利用电化学分析仪,通过测定外电路电流研究了渣中 FeO 含量、温度以及外电路电阻对熔渣中 FeO 电化学还原的影响．结果表明：在实验条件下,温度越高,渣中 FeO 含量越高,外电路电阻越小,熔渣电化学还原就越快．实际终还原率达95%以上．提出了可控氧流冶金中的一种还原方法,发展了可控氧流冶金理论．

关键词：熔渣氧化锆原电池电化学还原

在线全文

学校读者我要写书评

暂无评论

纳米晶镁粉的吸放氢动力学模型分析

稀有金属材料与工程 2007年第10期36卷 1802-1806页

作者：刘静李谦周国治林根文上海大学材料科学与工程学院上海200072

利用一种新模型分析了纳米晶镁粉的吸放氢动力学,量化了球磨和添加剂Pd对镁粉吸放氢动力学性能的改善效果。结果表明,球磨能大幅度降低氢化反应活化能,提高镁粉的氢化速率30倍。添加1%(质量分数)Pd的纳米镁粉(30nm)的吸放氢速率比未添... 详细信息

利用一种新模型分析了纳米晶镁粉的吸放氢动力学,量化了球磨和添加剂Pd对镁粉吸放氢动力学性能的改善效果。结果表明,球磨能大幅度降低氢化反应活化能,提高镁粉的氢化速率30倍。添加1%(质量分数)Pd的纳米镁粉(30nm)的吸放氢速率比未添加Pd的纳米镁粉(30nm)的吸氢速率提高6.6倍。模型计算出30nmMg-1%Pd(质量分数)合金的吸氢活化能为38.74kJ/molH2。

关键词：储氢合金纳米晶镁粉吸放氢动力学模型