ZHENG Chaogui JIN Jun YE Yupu Department of Chemistry
,
Peking University
,
Beijing
,
China Dept.of Chemistry
,
Peking University
,
Beijing
,
China
金属学报(英文版)
The liquidus of ternary system NdCl_3-MgCl_2-LiCl has been determined by means of DTA.It was found that there are two surfaces corresponding to the primary crystallization of NdCl_3 and α-(MgCl_2,LiCl)respectively,and a univariant line related to the secondary crystallization with a minimum M(68.5 wt-% NdCl_3,2.7 wt-% MgCl_2,28.8 wt-% LiCl_2 441℃)in the system.
关键词:
NdCl_3
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null
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null
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ZHANG Qiyun
,
LIU Shuqi
,
XU Yaping Peking University
,
Beijing
,
China professor
,
Department of Chemistry
,
Peking University
,
Beijing
,
100871
,
China
金属学报(英文版)
The features of Cu_6Sn_5 growing slowly at lower temperature and growing rapidly up over 350℃,and or Cu_3Sn growing at higher temperatures,bave been detailedly observed under SEM.The increase of Pb content seems to inhibit sequentially the growth of Cu_6Sn_5 in Pb-Sn alloy.
关键词:
Cu
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null
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null
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null
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ZHENG Chaogui BAO Chenglin QIAO Zhiyu YE Yupu Peking University
,
Beijing
,
China 1 University of Science and Technology Beijing
,
Beijing
,
China Associate Professor
,
Department of Chemistry
,
Peking University
,
Beijing 100871
,
China
金属学报(英文版)
Five fields corresponding to the primary crystallization of PrCl_3,Sr_3PrCl_9,α(SrCl_2, CaCl_2),α_1(CaCl_2,SrCl_2)and α_2(SrCl_2,CaCl_2)respectively,six univariant lines related to the secondary crystallization,one ternary eutectic(48.0 wt-% PrCl_3,23.5 wt-% SrCl_2; 590℃)and ternary peritectic point(45.5 wt-% PrCl_3,24.5 wt-% SrCl_2;614℃) were determined by DTA.Attempts were also made to explore the rule governing the alteration in the phase diagram containing rare earth chloride,formation of compound and its stability by means of polarization and counter-polarization.
关键词:
PrCl_3
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null
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null
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ZHENG Chaogui LIU Hongping YE Yupu(Y.P.Yeh) Peking University
,
Beijing
,
ChinaQIAO Zhiyu University of Science and Technology Beijing
,
Beijing
,
China ZHENG Chaogui Dept.of Chemistry
,
Peking University
,
Beijing 100871
,
China
金属学报(英文版)
Three surfaces corresponding to the primary crystallization of PrCl_3,CaCl_2 and MgCl_2 respectively,3 univariant curves related to the secondary crystallization and a ternary eutectic(44.8 wt-% PrCl_3,31.8 wt-% CaCl_2,546℃)were found in system PrCl_3-CaCl_2-MgCl_2 by means of DTA.A reaction occurs in this system: L=PrCl_3+CaCl_2+MgCl_2.
关键词:
PrCl_3-CaCl_2-MgCl_2
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null
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ZHANG Qiyun LIU Shuqi LAN Tie FU Yuchuan Peking University
,
Beijing
,
China ZHANG Qiyun
,
Professor
,
Department of Chemistry
,
Peking University
,
Beijing
,
China
金属学报(英文版)
A study on the interfacial activity behavior of flux during aluminium brazing has been made by using metallography,SEM and electron prob techniques.The results show that the activity, of a flux is caused by the wetting of base metal with the liquid heavy metal reduced from the flux,thus,some regions of liquid alloy created,at which no aluminium oxide film covers on the surfaces.The reduced metal drops are finally trapped in the fillet.The size of the metal drops increases with the decrease of brazing temperature.
关键词:
aluminium brazing
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null
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By ZHANG Yi WANG Yingxia HUA Tongwen Institute of Chemical Metallurgy
,
Academia Sinica
,
Beijing
,
100080
,
China.Department of Chemistry
,
Peking University
,
Beijing
,
100871
,
China.To whom correspondence should be addressed.
材料科学技术（英）
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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ZHANG Qiyun HAN Wanshu LIU Junkang Peking University
,
Beijing
,
China ZHANG Qiyun Professor
,
Dept.of Chemistry
,
Peking University
,
Beijing 100871
,
China
金属学报(英文版)
The interaction between Cu and liquid Sn was studied by microstructure observation.The curve of the dipping time with related to dissolving and diffusion of Cu in liquid Sn is given. The Cu dissolves rapidly in liquid Sn at the beginning,then an intermetallic compound Cu_6Sn_5 forms,and the dissolving follows to slow down.At temperature up to 350℃,the hard feather-like Cu_6Sn_5 is sharply growing up and speads through the dipped Sn laver.The way to inhibit the growth of the intermetallic compound Cu_6Sn_5 was also approached.Thus,on the above mentioned basis,the physical meaning of the wetting curve traced by the meniscograph wettability tester has been derived as film detaching,Cu dissolying and Cu_6Sn_5 growing.
关键词:
Cu
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null
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null
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