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Kinetics of α-FeO(OH)Formation in Weak Acidic Medium

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 , null , null , null

Work Functions of Pd_(83.5)Si_(16.5)and Cu_(70)Ti_(30)Glassy Alloys

By FENG Benzheng YANG Deqing Institute of Precious Metals , Kunming , 650221 , Yunnan , China.Physics Department , Yunnan University , Kunming , China.To whom correspondence should be addressed.

材料科学技术（英文）

The work functions before and after crystallization of two glassy alloys,Pd_(83.5)Si_(16.5) and Cu_(70)Ti_(30) have been measured by means of the con- tact potential difference method in the secondary electron field at room temperature under 10~(-5) Pa vacuum.The results show that the work functions of both glassy alloys are higher than those of the corresponding crystalline alloys.

关键词: work function , null , null

TEM Studies on Martensitic Transformation in Fe-Cr-W-V-C Alloy

WU Shanghua LIU Yumen Materials Science Institute , Zhongshan University , Guangzhou , 510275 , China.Department of Materials Science and Engineering , Xi'an Jiaotong University , Xi'an , 710049 , China.To whom correspondence should be addressed.

材料科学技术（英文）

The martensitic transformation in Fe-Cr-W-V-C alloy has been investigated by TEM.The habit plane of martensite is near (252)_f, the austenite/martensite orientation relationship is Kurdjumov-Sachs'.In the martensite plates there are twins on (112)[ 1]_b,dislocation tangles and the lattice defects on (011)_b plane.In the austenite near the growing martensite plates,the dislocations with high density and stacking faults can be observed. The substructure of martensite may probably be the result of accommodation deformation during martensitic transformations.

关键词: martensite , null , null , null

Wear Behaviour of CTC/FeCrCSi Composite

WANG Huaming JI Jialin ** Institute of Metal Research , Academia Sinica , Shenyang.110015 , China.*** Department of Mechanical Engineering , Xi'an Jiaotong University , Xi'an 710049 , China.To whom correspondence should be addressed.

材料科学技术（英文）

To bring the excellent abrasion-resistant po- tential of carbide into full play,composites of cast tungsten carbide(CTC)grains based on mainly plate martensite and high Cr,W white cast iron are made on substrate of grey iron by cast-in-place hardfacing process.Results of high-stress two-body and three-body abrasion show that:(1) Base alloy microstructures have overwhelming dominating effects on abrasion resistances of the composites in two-body and especially three-body abrasion systems.(2)All composites have very ex- cellent abrasion-resistances which increase drasti- cally with the increase of CTC grain size.In case of the same CTC grain size,composite based on martensite white cast iron is much more wear-resistant than that based on mainly plate martensite although the volume fraction of CTC grains in the latter is considerably larger than that in the former.In three-body abrasion system,load has little effect on wear rate for composites based on martensite white cast iron,but wear rate of conventional wear-resistant materials increases linearly in a very steep slope as the nominal stress increases.

关键词: abrasion , null , null

Microstructure of the Ionic Discharge of Oxygen on Graphite Anode in Aluminium Electrolysis

By ZHANG Mingjie ZHAI Yuchun OIU Zhuxian LIU Honglin CHEN Nianyi Northeast University of Technology , Shenyang , 110006.China.Shanghai Institute of Metallurgy , Academia Sinica , Shanghai , 200050 , China.To whom correspondence should be addressed.

材料科学技术（英文）

With the SCF-ab initio and EHMO method used in quantum chemistry, the total energy and charge distribution are calculated for O ions which are adsorbed on the different positions of various C lattices. Furthermore, the microstructure is dis- cussed for O ions discharging on the graphite anode.

关键词: ionic discharge , null , null

Metallurgical Reaction Characteristic for the Combined Blowing Process of Top-Bottom Blown Oxygen and Bottom Blown Natural Gas

YAN Guongting TA NG Ping ZHANG Shujun Chongqing University , Chongging , 630004 , China.To whom correspondence should be addressed.

材料科学技术（英文）

The experiment was carried out in a combined blowing converter.The natural gas was supplied as the cooling medium for the bottom lance.The blow- ing practice of medium P hot metal (0.30-0.85% [P]) indicated that with better stirring at the bottom of the converter and lower P_(CO),this steelmgking process was favorable to reduce the amount of [C] and [O] and increase the (P_2O_5)/[P]. The maximum rate of dephospborization might be high up to 0.0a5%/min and the P content in steel could be reduced to lower than 0.03% by single slag-forming operation.

关键词: combined blowing process , null , null

Reduction Kinetics of Nickel Sulphide

By LIU Zhonghua LIU Chunpeng Department of Metallurgy , Kunming Institute of Technology , Kunming , 650093 , China.To whom correspondence should be addressed.

材料科学技术（英文）

Reduction kinetics of Ni_3S_2 was experimen-tally studied by following the time required forcompletion of the hydrogen reduction reaction inthe presence of calcium oxide.A simple empiricalintegration equation,derived for describing the ef-fect of CaO/S molar ratio,temperature,hydrogenconcentration and the average diameter ofNi_3S_2 grains,may be shown as following:t_(X=1)=2.317×10~(-6)d_(Ni_3S_2) C_(H_2)~(-1)β~(-2.29)e~(13710/T),minThe reduction reaction is of first order with respectto hydrogen concentration,and the apparent reac-tion activation energy is 114.0 kJ/mol.A great ma-jority of metallic Ni reduced from Ni_3S_2 is distrib-uted in the products evenly.

关键词: kinetics , null , null

Low Energy Dislocation Structure in Deformed Metals

DIAO Xiaoxue XING Xiusan ** Department of Applied Physics , Beijing Institute of Science and Technology , Beijing , 100081 , China.To whom correspondence should be addressed.

材料科学技术（英文）

In this paper,the dislocation distribution struc- ture in deformed metal is discussed.The flow stress of material for the heterogeneous dislocation distri- bution which tends to the flow stress for the homo- geneous dislocation distribution in the limiting case is derived.The causes and the effects of the long range internal stresses are discussed.The total deformation energy of material system is obtained and the trend of evolution of dislocation distribu- tion in deformed metals is discussed simultaneously. No micromechanisms of dislocations are involved in the discussion,therefore the theory developed in this paper is universal.

关键词: Dislocation structure , null

Characteristics of BF Burden-flow at Material Gate of Bell-less Top

D U Hegui D U Gang Northeast University of Technology , Shenyang , 110006 , China.To whom correspondence should be addressed.

材料科学技术（英文）

The influence of material gate position in bur- den-flow rate has been studied by simulating exper- iments.A mathematical model describing the char- acteristics of burden-flow at the material gate of bell-less top blast furnace(BF)is established in this paper,in an attempt to solve the problems in bur- den distribution,especially to eliminate the over- lapping or disconnection of the burden at the be- ginning and at the end of a ring,which plays a quite important role in the blast furnace operation.

关键词: blast furnace , null , null , null

Effect of Y-containing Phase in Fe-20Cr-4Al-Y Alloys on Microstructure and Embrittlement

LI Bei YAN Yuxin MENG Guang'en WU Shuangxia TANG Fenghuang Baotou Research Institute of Rare Earth , Baotou , 014010 , China.To whom correspondence should be addressed.

材料科学技术（英文）

In Fe-20Cr-4Al-0.5Si-(0.13-0.73)Y alloys,a new phase consisting of 15.8 wt-% Y,65.4 wt-% Fe,12.6 wt-% Cr,4.4 wt-% Al and 1.4 wt-% Si was observed with its Y-content and crys- tal structure being identical with those of YFe_9 phase basically and the microhardness being 4-5 times higher than that of α-phase matrix.It is a kind of stable particles (2-10 μm) dispersed over the matrix. For Y-free or less alloy,the plasticity dropped sharply after high temperature treatment,while the plasticity is retained for the alloys containing 0.41-0.73 wt-% Y treated below 1340℃,because the Y-containing particles can strongly prevent from grain growth,and dislocation annihilation, and trap impurities.If treatment temperature is higher than 1340℃,however,these actions will dis- appear owing to the melting of the particles.

关键词: Fe-Cr-AI-Y alloy , null , null

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