材料期刊网

THE SYNERGISTIC INHIBITION STUDIES OF SEVERAL AMINES AND CHLORIDE ION ON IRON IN THE ACIDIC PERCHLORIDE SOLUTIONS

J.H.Dong 1) , J.Y.Chen 2 , 3) and. C.N.Cao 1) 1) State Key Laboratory for Corrosion and Protection of Metals , Institute of Corrosion and Protection of Metals , The Chinese Academy of Sciences , Shenyang 110015 , China 2) The International Center for Materials Physics , CAS , Shenyang 110015 , China 3) Shenyang Normal College , Shenyang 110031 , China

金属学报(英文版)

The effect of chloride ion on the corrosion inhibition of iron caused by dencylamine(DA), dipentylamine(DDA) and dodecylamine(DPA) has been investigated by measuring the inhibitory coefficients for the anodic and cathodic processes at corrosion potential. It has been shown that the major synergistic inhibition effects between amines and chloride ions occur in the cathodic process, very weak in the anodic process. The anodic inhibition mechanism follows the competing adsorptive model, while the cathodic inhibition mechanism follows the cooperative adsorptive model.

关键词: synergistic inhibition , null , null

Development of rapidly quenched soft magnetic materials in China

Shaoxiong ZHOU

材料科学技术（英文）

The discovery of the first Fe-based ferromagnetic amorphous alloy in 1966 had made an impact on conventional magnetic materials because of its unique properties. Since then, a number of amorphous magnetic materials have been successfully developed and used in a wide variety of applications. A brief review of R & D activities on amorphous soft magnetic materials in China is given from the beginning to the present in a somewhat chronological order, followed by a brief introduction to their applications on electric and electronic industries. An analysis and a prospect of Chinese market of such amorphous materials are also presented.

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CURRENT STATUS OF HIGH-RESOLUTION ELECTRON-MICROSCOPY AND ITS APPLICATIONS TO MATERIALS SCIENCE AND CONDENSED MATTER PHYSICS

材料科学技术（英文）

The present paper summarizes the current status of high resolution elect;on microscopy ( HREM) and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction, subnanometer level analysis, image simulation and image processing.

关键词: juxtaposed pentagonal antiprisms;two-dimensional quasicrystal;domain;boundary structures;close-packed phases;nanocrystalline materials;crystal-structure;copper oxidation;initial-stage;translational;symmetry;rotational symmetry

Current Status of High Resolution Electron Microscopy and Its Applications to Materials Science and Condensed Matter Physics

Douxing LI and Hengqiang YE (Laboratory of Atomic imaging of Solids , Institute of Metal Research , Chinese Academy of Sciences , Shenyang , 110015 , China)

材料科学技术（英文）

The present paper summarizes the current status of high resolution electron microscopy (HREM)and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction,subnanometer level analysis, image simulation and image processing.

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CORRELATION BETWEEN STRESS COMPONENTS AND STRESS CORROSION CRACKS IN BRASS Lecturer,Department of Materials Physics,University of Science and Technology Beijing,Beijing 100083,China

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 , null , null , null

Defect model for a tetragonal Co2+ impurity center in AgCl crystal

Materials Science and Engineering B-Solid State Materials for Advanced Technology

The EPR g-factors g(parallel to), g(perpendicular to) and hyperfine structure constants A(parallel to), A(perpendicular to) for a tetragonal Co2+ impurity center (i.e. Co2+ (II) center) in AgCl crystal are calculated by using the perturbation formulas of EPR parameters for the 3d(7) ion in tetragonal symmetry obtained from the cluster approach. Based on the calculations, the defect model for the center is suggested as a substitutional Co2+ ion associated with a nearest neighbour O2- ion. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词: defect model;electron paramagnetic resonance;crystal-field theory;ligand-field theory;Co2+;AgCl;transition

Analysis of Ground-State Zero-Field Splitting for Mn(2+) in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O)

Chinese Physics Letters

The electron paramagnetic resonance spectra of trigonal Mn(2+) centers in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) crystals are studied on the basis of the complete energy matrices for a d(5) configuration ion in a trigonal ligand field. It is demonstrated that the local lattice structure around a trigonal Mn(2+) center has an elongation distortion along the crystalline c(3) axis, and when Mn(2+) is doped in the ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) crystals, there is a similar local distortion. From the EPR calculation, the local lattice structure parameters for trigonal Mn(2+) centers in ZnNbOF(5)center dot 6(H(2)O) and CoNbOF(5)center dot 6(H(2)O) are determined.

关键词: phase-transition;ions;complexes;crystals;spectra;fe-3+;epr

EPR paramaters and defect structure of the trigonal Ti2+ center in ZnS

Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The axial Ti2+ center in a nearly wholly cubic ZnS crystal is assigned to the Ti2+ ion on the hexagonal site of wurtzite structure caused by stacking faults. On the ground of the assignment, the EPR parameters (zero-field splitting D, g factor g(parallel to) and g-anisotropy Delta g = g(parallel to) - g(perpendicular to)) of the axial Ti2+ center are calculated from the high-order perturbation formulas based on the cluster approach for the EPR parameters of 3d(2) ion in trigonal symmetry. From the calculations, the local atom-position parameter u(loc) (which is different from the corresponding parameter u in the host wurtzite structure) and hence the defect structure of the Ti" center are estimated. The results (the calculated EPR parameters and the defect structure) are discussed. (c) 2004 Elsevier B.V. All rights reserved.

关键词: electron paramagnetic resonance (EPR);local lattice distortion;crystal- and ligand-field;Ti2+;ZnS;electron-spin resonance;superposition model;zinc-sulfide;crystals;absorption;ions;fe3+;site

Studies on the EPR parameters for the rhombic Co2+ center in magnesium acetate

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The electron paramagnetic resonance (EPR) g factors g(i) (i = x,y,z) and the hyperfine structure constants A(i) for the rhombic Co2+ center in magnesium acetate are theoretically studied from the perturbation formulas of these parameters for a 3d(7) ion under rhombic symmetry. In these formulas, the contributions from the admixture among different states, covalency effect and rhombic crystal-fields are taken into account. The related crystal-field parameters are determined from the superposition model and the local geometrical relationship of the impurity center. The calculated results show reasonable agreement with the observed values. In addition, the nuclear quadrupole interaction constant is analyzed, and its negative sign is verified theoretically.

关键词: electron paramagnetic resonance (EPR);crystal- and ligand-fields;Co2+;magnesium acetate;atomic screening constants;paramagnetic-resonance;superposition model;aqueous-solutions;scf functions;g-tensor;crystal;fields;sites;liyf4

EPR investigation of the structure of a rhombic Co2+ center in an NaF crystal

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The local structure of the rhombic Co2+ center in NaF crystal is investigated by using the perturbation formulas of electron paramagnetic resonance (EPR) g factors g(i) (i - x,y,z) and hyperfine constants A(i) for a 3d(7) (Co2+) ion in rhombic octahedral symmetry based on a cluster approach. In these formulas, the contributions from the admixture among different states, covalency effect as well as rhombic crystal field are included. By studying the EPR data of the rhombic Co2+ center, one can reasonably obtain the local structural (or rhombic distortion) parameters DeltaR(c)(approximate to 0.268 Angstrom) for the central Co2+ and DeltaR(p)(approximate to 0. 181 Angstrom) for the two F- ions along [100] and [010] axes closest to the Na+ vacancy V-Na. The reasonableness of the results is also discussed.

关键词: local geometry;electron paramagnetic resonance (EPR);crystal- and;ligand field theory;NaF;Co2+;atomic screening constants;superposition model;scf functions;parameters;electrons;resonance;ions;cr3+