DU Weixi HAN Qiyong JIANG Qing ZHANG Zhongzhi ZHONG Weizhen LIU Shaoshou Jilin University of Technology
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Changchun
,
China [Originally published in ACTA METALL SIN (CHINESE EDN) 24(5) 1988pp B313—B319
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received 17 Octorber 1986
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in revised form 3 April 19871 Beijing University of Science and Technology
金属学报(英文版)
Electrolytic extraction-radiometry and microradioautography techniques were used to study the distribution of nodulizing element Ce and anti-nodulizing element S in phases of high purity Fe-C-Si alloy.The results show that,besides forming inclusions,most of Ce atoms concentrate in graphite firstly.As the Ce content increases,the concentration of Ce in graphite tends to saturate,relatively large amount of Ce dissolves in the alloy.Usually,the sulphur also concentrates in graphite.However,it may exist in the form of FeS at the eutectic colony boundaries,if the concentration of S is at a quite high level.Very little amount of S dissolves in the alloy.The morphology of graphite depends upon the degree of saturation of Ce.It appears as nodular when Ce was saturated and,as vermicular while it was semi-saturated.
关键词:
Ce.S.Fe-C-Si alloy
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null
QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
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Beijing
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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
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null
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null
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Surface & Coatings Technology
Well-adhered gamma-Al2O3 coating layers can be formed on FeCrAl metallic supports for the preparation of structured catalysts in diesel particulate filter (DPF) systems using a three-step method-pre-oxidation, primer deposition and coating deposition. The optimal pre-oxidation is at 950 degreesC for 10 h; the optimal primer sol calcination is at 800 degreesC for 3 h; and the optimal gamma-Al2O3 slurry calcination is at 900 degreesC for 2 h. If the oxidation temperature is 1050 degreesC, only 0.5 h is required to obtain almost the same coating adhesion level as at 950 degreesC for 10 h. The data concerning effects of the major preparation parameters (the pre-oxidation time, temperature, primer calcination temperature and the coating calcination temperature) are presented herein. The coating adhesion was measured by ultrasonic adhesion, thermal shock and interface shear strength tests. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
gamma-Al2O3 washcoat;metallic support;adhesion;oxidation;thickness;stress
