By ZHANG Yi WANG Yingxia HUA Tongwen Institute of Chemical Metallurgy
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Academia Sinica
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Beijing
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100080
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China.Department of Chemistry
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Peking University
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Beijing
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100871
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China.To whom correspondence should be addressed.
材料科学技术（英文）
The kinetics of α-FeO(OH) formation in weak acidic medium was studied.The effects of the initial concentration,temperature,pH value,partial pres- sure of oxygen,air flow rate and agitating intensity on the oxidation rate of Fe(OH)_2 suspensions have been investigated.It is confirmed that the reaction order for Fe(Ⅱ) is zero at the stage of α-FeO(OH) seeds formation,and about 0.5 at the stage of the seeds growth,and in the whole process partial pres- sure of oxygen appears in first order.The activation energy is determined.The dissolution-oxidation equilibrium which exists in the process of seeds formation has been suggested,by which the zero order reaction for Fe(Ⅱ) and the plateau in the pH-t curve were explained.Physical process is the rate-determining step of the heterogeneous reaction.The study on the kinetics of α-FeO(OH) formation may provide some fundamental informa- tion for the reactor design,the engineering amplifi- cation and the optimization control in the industrial process.
关键词:
kinetics
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null
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王丽
,
吴希文
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张晨鼎
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张通
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简丽
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武朝军
,
周涛
稀土
doi:10.3969/j.issn.1004-0277.1999.02.003
采用湿渣法研究了0℃时碘化钇(YI3)-乌洛托品氢碘酸盐(C6H12N4.HI)-水(H2O)的三元体系相平衡,绘制了该体系的等温溶解度相图,相图分析结果表明,该体系中有组成为YI3.C6H12N4.HI.14H2O的配合物生成,对所得配合物进行了化学分析、X-射线粉末衍射、红外光谱、差热-热重分析,测定了其密度、晶体轴性,确定了配合物结构中的配位关系.
关键词:
相平衡
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碘化钇
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乌洛托品氢碘酸盐
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配合物
LIU Chunpeng XU Yousheng HUA Yixin Kunming Institute of Technology
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Kunming
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650093
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China.
材料科学技术（英文）
In applying the microwave radiation to extractive me- tallurgy,it is essential first of all to find the extent of microwave energy absorbed by various minerals experi- mentally.In this paper,more than 25 kinds of common useful minerals have been individually irradiated by a 500 W,2450 MHz microwave source in an enclosed quartz crucible to ascertain their heating temperature in a definite time.In addition,the reduction and cbloridization tests were also carried out on the titanomagnetite concentrate and pentlandite with microwave heating,respectively. These experiments indicate potential applications of util- izing microwave energy in extractive metallurgy.
关键词:
microwave radiation
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null
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Z. T. Ma and D. Janke(Institute of Iron and Steel Technology
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Freiberg University of Mining and Technology
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Germany)
金属学报(英文版)
Useder certain conditions, nonmctallic inclusions such as oxides, sulfides, nitrides and carbides are no longer harmful to sted service properties. With the new concept of oxide metallurgy, these properties can be improved by generating fine oxide inclusions which serve as heterogeneous nuclei for sulfide and fine ferrite[1-4]. A novel continuous casting (CC) process is expected to be created with the utilization of oxide metallurgy. This is also useful for the forthcoming technologies of direct rolling and near-net-shape casting. The main idea of oxide metallurgy consists of an alternative oxidation technology. It is based on steels treated by complex metals such as Ti, Zr, Ti-Zr alloys and rare earth metals. The selected deoxidants should follow the required conditions which are concluded in this paper.
关键词:
oxide
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Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
Yong LIU
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Lifang CHEN
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Weifeng WEI
,
Huiping TANG
,
Bin LIU
材料科学技术（英文）
Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy (PM) process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of Ti-4.5Al-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct.
关键词:
Powder metallurgy titanium alloy
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