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MgB_2 superconducting materials synthesis process

Author: HuangYong
Tutor: LiuXinYu
School: Central South University
Course: Materials Processing Engineering
Keywords: MgB2 Synthesis process Mechanical alloying Solid-state reaction Rare earths
CLC: TM26
Type: Master's thesis
Year: 2005
Downloads: 149
Quote: 0
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Abstract


The research by mechanical alloying and solid state reaction method , powder metallurgy route , prepared MgB 2 doped with different rare earth (Y, Pr) content of rare earth - of MgB 2 superconducting material MgB 2 synthesis process of a thorough and systematic study . The help of modern analytical instrumentation, mechanical alloying of Mg-B powder mixture and the solid phase reaction the synthetic material sintering process , oxidation behavior , the secondary sintering process , trace rare earth doping of MgB 2 the structure of a thorough and systematic study . The results show that : the atomic ratio of Mg: B = 1:2 mixed powder during milling, can be obtained even amorphous microcrystalline powder MgB 2 . The MgB 2 mechanical alloying mechanism of diffusion solid solution . The ball feed ratio a MgB 2 Synthesis obvious , agate ball milling , ball to powder ratio of 20:1 , canning capacity of the tank capacity 1/2 easier to form MgB 2 . To maintain the volume of ball material than the same circumstances , the use of a large mass of the stainless steel balls instead of agate ball milling can improve the impact energy , greatly accelerated MgB 2 the formation . The prepared superconducting MgB 2 block material by solid -phase sintering , during the preparation process must prevent the insulation in the process of Mg oxide and volatile , and high temperature MgB 2 exploded . The synthesis process must be carried out under a protective atmosphere or vacuum state . In an argon stream under a protective atmosphere , Mg : B = incubated at 1:1.5,800 ° C 2h is the optimal conditions of the synthesis . In a sealed quartz tube , Mg : B = incubated at 1:1.95,800 ° C 1h is the best conditions of the synthesis . Density of the material can be improved by the secondary sintering . Trace rare earth doped MgB 2 in the formation of the solid solution of MgB 2 structure is not too much of an impact . The rare earth content can increase the bulk density .

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CLC: > Industrial Technology > Electrotechnical > Electrical materials > Superconductors, superconductor materials
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