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Research on Synthesizing MnOOH Nanotubes with Self-sacrificing Template Route

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 1-4
Monoclinic MnOOH nanotubes were synthesized for the first time by oxidizing the self-sacrificing template of β-MnO2 nanotubes in stainless steel autoclave at 200℃ for 48 h. The prepared samples were characterized by XRD,TEM,SAED,FESEM, HRTEM and EDS. The results show that the samples are pure single-crystal MnOOH nanotubes,having the diameters of 200-500 nm and the lengths of several microns.
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Research on Synthesizing Bi_2S_3 Nanorods by Complex Solvothermal Process

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 5-7
Large-scale Bi2S3 nanorods were synthesized by the complex solvothermal process using copper reagent (sodium diethyldithiocarbamate) as sulfur source,bismuth nitrate as bismuth source,and glycerolwater system as solvent. The product was investigated by X-ray powder diffraction (XRD),transmission electron microscopy (TEM),field emission scanning electron microscopy (FESEM) and so on. The results show that the prepared sample is purely of orthorhombic crystal phase. The well-dispersed single-crystal nanorods are obtained, having the lateral sizes of 30-50 nm and the axial sizes of several microns. The formation mechanism of Bi2S3 nanorods is also discussed. It is concluded that both the complex solvent of glycerol-water and the surfactant of PVP have important influences on the morphology and size of Bi2 S3 single -crystal nanorods.
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Research on the Microstructure of Tungsten Oxides

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 8-11
The microstructure of tungsten oxides was investigated by using scanning electron microscopy, transmission electron microscopy and so on. The results show that different tungsten oxides, including violet tungsten oxide,blue tungsten oxide and yellow tungsten oxide, are of different microstructure. Especially,violet tungsten oxide is of particular monocrystal bar structure and suitable for producing fine tungsten powders.
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Characteristics of β_2 Phase in the Casting Alloy Ti-47Al-2Cr-2Nb and its Effect on the Alloy Thermal Stability

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 12-15
The characteristics of β2phase and its effects on the alloy thermal stability were investigated in the casting alloy Ti-47Al-2Cr-2Nb with industrial application value. The results show that β2 phase is with high Cr content and of dispersive distribution and continuous linear morphology in the TiAl alloy lamellar microstrueture. No strict coherent orientation of a2 and 7 phase is kept in β2 phase. By aging treatment (1 150℃ and 48 h),the lamellar structure is dissolved and coarsened preferentially at the phase interface between β2 and (a2+γ). During the heating process of (a2+γ) phase region,a2 particles are also precipitated and grown preferentially at the boundary. Accordingly,the addition of β2 phase is harmful for the thermal stability of TiAl alloy.
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Numerical Simulation and Technical Study of Superplastic Forming/Diffusion Bonding for Ti Alloy Sheet

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 16-19
The finite element Marc software was used to numerically simulate the processes of superplastie forming/diffusion bonding of TC4,a Ti alloy sheet. Based on the optimized pressure-time (p-t) curve obtained from simulation,the following experiments of superplastic forming/diffusion bonding were carried out. The experimental results show that the optimal technological parameters of TC4 superplastic forming/ diffusion bonding are as follows: superplastic forming θ=900℃,p=2. 5 MPa,t=790 s;diffusion bonding θ=900℃ ,p=3 MPa,t=80 min.
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Technological Experiment of Mo Recovery from Bi Slag by Water Quench Leaching

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 20-22
The Mo recovery process was tested from the smelting slag of Bi reverberatory furnace by water quench leaching, and the tested process was compared with the present soda leaching process. The results show that extracting Mo from Bi slag by direct water quench leaching is technically reliable and economically feasible to replace soda leaching.
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Optimization Measures of the Technology and Equipment for Molybdenum Wire Production and their Implementation Effects

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 23-25
In view of the product quality problems from the molybdenum wire production line of rolling blooming-oversize turnplate stretching,the production technology and equipment are analyzed and studied. Furthermore,many optimization measures are carried out and their excellenteffects have also been proved by production practice.
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Determination of Trace Impurity Elements in the Li-Pb Alloy

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 29-32
The content of trace impurity elements-Fe,Na,Al, Mg-in the alloy Li17 Pb83 was measured by inductively coupled plasma emission spectroscopy (ICP-AES). The optimization of measuring parameters was explored as well as the type and dosage of acid. And the interference effect of coexistent elements on the analysis result was also studied. The results show that the mass fractions of Fe,Na,AI,Mg in Li17Pb83 are respectively 0. 003%,0. 005 8%,0. 002 6% and 0. 002% ,when carrier gas pressure is 0.25 MPa,generator power 1.3 k W,observation height 10 mm above the coil, the volume ratio of hydrochloric acid to nitric acid 4 : 1 and the total acid concentration 10%.
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Cobalt Determination of Cemented Carbide by Spectrophotometry with Picramazochrom as the Chromogenic Reagent

Rare Metals and Cemented Carbides | Vol., Issue 3, 2009 | pp. 33-35
The chromogenic reaction between picramazochrom and cobalt was studied with plcramazocnrom as the chromogenie reagent. In the ammonium citrate-ammonia solution of pH10. 0,cobalt reacted with picramazochrom to form a green complex,which exhibited the maximum absorption wavelength at 670 nm with an apparent molar absorptivity of 2.62×10^4L /(mol·cm). And Beer's law was obeyed in the range of 0-50μg/25 mL cobalt. When the cobalt content in cemented carbide was determined directly by the spectrophotometry with picramazochrom,the relative standard deviation was between 1.4 % and 2.1%.
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