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KINETICS OF REACTION BETWEEN Cu_2S AND Cu_2O

LU Yuehua Kunming Institute of Precious Metals , Kunming , ChinaLIU Chunpeng Kunming Institute of Technology , Kunming , China Research Assistant , Laboratory No.1 , Kunming Institute of Precious Metals , Kunming 650031 , China

金属学报(英文版)

Reaction between Cu_2S and Cu_2O was investigated at 1150 to 1250℃.The reaction rate in- creases with the increase of surface area of Cu_2O grains and depends unobviously on temper- ature.At the suggestion of controlling step of reaction rate being oxygen diffusion through the liquid layer along reaction boundaries,two final kinetical equations would be made as follows: x=6.69×10~(-2)At for 0<α<0.74 and ln(l-α)=-A(9.83×10~(-2)t+1.76)for 0.74<α<1,where α is SO_2 evolved in time t and A is surface area of Cu_2O particles.

关键词: Cu_2O , null , null

INTERNAL OXIDATION BEHAVIOR OF Pd-40Ag-1M(M=Zr,Y)ALLOYS

NING Yuantao LI Yongnian Kunming Institute of Precious Metals , Kunmmg , China Professor , Kunming Institute of Precious Metals , Kunming , Yunnan , China

金属学报(英文版)

The internal oxidation behavior of Pd-40Ag-1M(M=Zr,Y)alloy wires has been studied in air at 800—1200℃.The relationship between the internal oxidation depth ξ and the reaction time t can be expressed as ξ= Kt~n,where n=0.5—0.75.The higher the temperature,the larger the value of n is.The active elements Zr and Y show different internal oxidation characters.For the alloys eontaining Zr,the oxidation rate along the grain boundaries is about twice as high as that in grains,and“lateral oxidation”exists along the grain boundaries.For the alloys containing Y,the oxidation rates in grains and along the grain boundaries are roughly the same,and there is no“lateral oxidation”along the grain bounda- ries.The activation energies of both alloys are in the range of 120—150kJ/mol.Some prop- erties for oxidized alloys were studied.The mechanisms of the internal oxidation were dis- cussed.

关键词: Pd-40Ag alloy , null , null , null , null

ROOM TEMPERATURE AND 750℃ ISOTHERMAL SECTION OF Ag-Pd-Gd(Gd≤25 AT.-%)PHASE DIAGRAM

ZHANG Kanghou CHEN Lili Kunming Institute of Precious Metals , Kunming , China ZHANG Kanghou , Kunming Institute of Precious Metals , Kunming 650221 , China

金属学报(英文版)

The room temperature section and the 750℃ isothermal section of the Ag-Pd-Gd ternary phase diagram containing 0—25 at.-% Gd are constructed by X—ray diffraction analysis and optical microscopy.Each section consists of 3 single phase regions,3 bi-phase regions and I tri-phase region respectively.

关键词: Ag-Pd-Gd ternary system , null