HUANG Dianbing
,
KONG Lingtan
,
LIN ZongcaiUniversity of Science and Technology Beijing
,
Beijing. China
金属学报(英文版)
The oxidation rate of magnetite concentrate is ery quick at the reaction beginning, but it becomes much slower when the reaction is conducted to a certain level because the product layer on the micro particles resists the oxygen diffusion greatly. This phenomena are proved through experiments. And a function is put forward to calculating the quivalent osmosing thickness of the product layer. Based on the function, a mathematical model is established for the whole range reaction process of magnetite in pellets. It is proved that this model fits the real process very well under any condition.
关键词:
Magnetite
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null
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WU Huawu
,
ZHUANG JingTsinghua University
,
Beijing. China
金属学报(英文版)
Bused on the consideration o (?) mass and volume of one atom, a new formula tor calculating the density of simple metal substance from their atomic structure parameters is established. The densities of 66 metals in the periodic table were calculated from this formula. The calculated results are in agreement with the measured values reported in literature. The advantage of the present formula over the others is brie fly discussed.
关键词:
density
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null
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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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null
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null
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LIANG Yong LI Ruiguo Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
ChinaInstitute of Corrosion and Protection of Metals
,
Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术(英文)
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
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null
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null
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null
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null
Yang LUO
材料科学技术(英文)
Due to continued growth in key markets, a broadening of application base and performance improvements, the market demands of NdFeB magnet increased steadily in 1998, and the global output of sintered NdFeB magnet exceeded 10,000 t, in spite of the economic recession in Asia. In 1998 China produced 3,850 t sintered NdFeB block magnet, with an annual growth rate of +22% over the output in 1997.
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