WANG Yanan Anshan Institute of Iron and Steel Technology
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Anshan
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ChinaSONG Weixi University of Science and Technology Beijing
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Beijing
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China WANG Yanan
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Laboratory of Metallography
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Anshan Institute of Iron and Steel Technology
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Anshan
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Liaoning 114002
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China
金属学报(英文版)
An observation under TEM was carried out of the hetero-particles and stripes inside of the vermicular graphite in cast iron specimens which were prepared by isothermally quenching in ice-salt-water.The hetero-particles and stripes,composed of almost pure Fe and a little Si, were found in the regions of the growth direction changing of the vermicular graphite.Many twins and dislocations were also observed to contribute to changing the growth direction and to providing the growth steps of the graphite respectively.
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vermicular graphite
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null
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WU Weitao Institute of Corrosion and Protection of Metals
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Academia Sinica
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Shenyang
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China.
材料科学技术（英文）
Interference layer metallography was used to identify the phases present in the aluminide coating on superalloy IN738LC. They are: two intermetallic aluminides NiAl and Ni_3Al, y-solid solution and a Cr-rich solid solution, two sulphides M_(23)C_6 and MC, and two sulphides (Al,Cr)_3S_4 and (Cr,Ti)_3S_4. ZnS and ZnSe are proposed to be vapor deposited onto the surface of the specimen to get good colour contrast and good light-dark contrast. The refractive index and absorption coefficient of all these phases have been detemined.
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coating
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Corrosion Science
The early stages of the evolution of atmospheric corrosion of carbon steels exposed in both a laboratory simulated and a natural atmosphere environment in Shenyang have been observed by in situ scanning electron microscopy. In the case of laboratory cyclic wet-dry tests, even though the chloride content level is very low, filiform corrosion is initiated in the early stage. The filiform corrosion grows in random directions, forming a network of ridges. White nodules nucleate and grow on the ridges during continued corrosion and eventually connect with each other to form the initial corrosion scale. Pits were also found on the surface beneath corrosion products. In the case of a natural atmospheric environment, both filiform corrosion and other localized corrosion, such as pitting and inter-granular attack take place in the initial stage. It is obvious that there is variety of localized corrosion in the initial stage of atmospheric corrosion. (C) 2007 Elsevier Ltd. All rights reserved.
关键词:
steel;atmospheric corrosion;initial stage;localized corrosion;in-situ;iron;electrolyte;thickness
Author S.T. TU
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J.M. Gong and X. Ling Nanjing University of Chemical Technology
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Nanjing 210009
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ChinaManuscript received 18 October 1998
金属学报(英文版)
In order to interpret the test results of crossweld specimens for application in practical welded components, the present paper studies the high temperature behavior of laboratory cross weld specimens in terms of the uniaxial material tests and numerical simulations. It is found that the crossweld specimen may be used for the high temperature strength assessment, but can hardly be used for life assessment of the practical welded components, which depends on the loading conditions of the components.
关键词:
high temperature
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null
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Materials Chemistry and Physics
The corrosion behaviour of CortenA weathering steel has been investigated using a laboratory accelerated test that involved cyclic wet/dry conditions in Qinghai salt lake water diluted 30 times The characteristics of the rust layers on tested samples were observed by SEM and EPMA analyzed by IRS and XRD and studied by polarization and EIS measurements The weight loss was almost linear indicating that the rust layer had no retarding effect on the corrosion process The crystalline components of the rust layers consisted primarily of beta-FeOOH magnetite (Fe(3)O(4)) and gamma-FeOOH As the corrosion proceeded the amount of beta-FeOOH decreased while that of magnetite and gamma-FeOOH increased XRD EDAX and EPMA indicated that the complex corrosion products magnesioferrite (MgFe(2)O(4)) and iowaite (Mg(4)Fe(OH)(8)OCl 4H(2)O) probably existed in the rust layer in which case they will have had an important Influence on the protectiveness of the rust layer The results of electrochemical measurements showed that the rust layer exhibited high reduction reactivity which facilitated the corrosion of weathering steel in the wetting process The large rust capacitance and small rust resistance indicated that the rust layer had a loose and porous structure which provided poor protection (c) 2010 Elsevier B V All rights reserved
关键词:
Elements;Corrosion test;Electrochemical techniques;Electron probe;low-alloy steels;atmospheric corrosion;carbon-steel;electrochemical;impedance;room-temperature;rust layers;iron;mechanism;products;environment
Surface & Coatings Technology
Using a halide-activated pack-cementation method but at a temperature (600 degrees C) noticeably lower than normal, an eta-Fe(2)Al(5) coating and two delta-Ni(2)Al(3) coatings with and without dispersions of CeO(2) nanoparticles were developed respectively on a low-carbon steel and the steel pretreated with an electrodeposited film of Ni or Ni-CeO(2). The erosion-corrosion (E-C) performance of the three aluminide coatings during 100 h exposure at similar to 600 degrees C in a coal-firing laboratory-scale fluidized-bed combustor (FBC) was investigated, by mounting the aluminized samples onto a rig which maintained rotation for accelerating the relative impacting speed of flying solid particles (mainly SiO(2) bed materials). The eta-Fe(2)Al(5) and the CeO(2)-free delta-Ni(2)Al(3) coatings experienced an unacceptable recession rate. Compared to the two CeO(2)-free aluminide coatings, the CeO(2)-dispersed delta-Ni(2)Al(3) coating offered profoundly improved E-C resistance, because the latter coating was not only strengthened by the CeO(2) dispersion and grain refinement, it also could grow a more adherent alumina scale. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Erosion-corrosion;CeO(2)-dispersion-strengthening;Aluminizing coating;Grain refinement;Hardening;Reactive element effect;oxidation resistance;reactive elements;alloy-steels;water-vapor;power-plant;nickel;combustion;mechanisms;additions;behavior
Xingzhong ZHAO
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Jiajun LIU and Baoliang ZHU (Tsinghua University
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Beiing 100084
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China)Cuiyuen WANG (Zhengzhou Research Institute of Mechanical Engineering
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Zhengzhou 450002
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China)
材料科学技术（英文）
The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-carrying capacity than oil B (imported from abroad). The X-ray diffraction (XRD) analyses of the worn surfaces showed that different extreme pressure (EP) lubricating films were formed on the surfaces when the rollers were lubricated with different oils under boundary Iubrication condition. The EP film of oil A was a composite film containing three compounds, FeO, FeSx and FeP, while oil B formed only a simple EP film of FePO4. The composite EP film showed lower shear strength and better antiwear property than the simple EP film,which brought about different wear resistance of the two wheel/rail lubricating oils.
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