Author C.D. Zhou1
,
2)
,
J.X. Yu1)
,
X.P. Dong1)
,
Y.H. Zhang1)
,
C.Q. Sun3) and T.F. Li4) 1) The State Education Commission Open Research Laboratory for High Temperature Materials and Testing
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China2) Shanghai Enhanced Lab of Ferrometallurgy
,
Shanghai University
,
Shanghai 200072
,
China3) Institute of Aeronautical Materials
,
Beijing 100095
,
China 4) Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
An investigation has been made on the tensile fracture behavior of oriented single crystal DD100 superalloy at 850. The appearance of the fracture surface of DD100 reflects the glide plane decohension fracture mechanism, which is different from the fracture of oriented DD100. The tensile strength and elongation are lower than the oriented DD100. Oxygen in air has little effect on the strength of DD100 but reduces the tensile elongation obviously. Oxygen does not affect the fracture mode of DD100 but strongly accelerates the process of fracture.
关键词:
single crystal superalloy
,
null
,
null
Journal of the European Ceramic Society
The hot corrosion behavior of Na2SO4-coated Ti2AlC was investigated by means of thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy/energy dispersive spectroscopy. This carbide displays good hot corrosion resistance below the melting point of Na2SO4 while the corrosion attacks become virulent when the salt is molten. A protectively continuous Al2O3 layer forms and imparts good corrosion resistance, and consequently, the corrosion kinetics is generally parabolic at 850 degrees C. However, porous oxide scales fail to protect the Ti2AlC substrate at 900 and 1000 degrees C. The segregation of sulfur at the corrosion scale/substrate interface accelerates the corrosion of Ti2AlC. Furthermore, a convenient and efficient pre-oxidation method is proposed to improve the high-temperature hot corrosion resistance of Ti2AlC. An Al2O3 scale formed during pre-oxidation treatment can remarkably restrain the infiltration of the molten salt into the substrate and prevent the substrate from severe corrosion attacks. (c) 2005 Elsevier Ltd. All rights reserved.
关键词:
Ti2AlC;Al2O3;corrosion;high-temperature oxidation;polycrystalline ti2alc;carbides;behavior;ti3alc2;alumina;phase
Materials and Corrosion-Werkstoffe Und Korrosion
In order to investigate the galvanic anodic protection (GAP) of ferrous metals (such as 410, 304 and 316 stainless steels) in acid solutions by doped polyaniline (PANi), separate doped PANi powder-pressed electrodes with different surface areas (the area ratio of the PANi electrode to stainless steel is between 1:1 and 1:2) have been prepared. These were coupled with ferrous metal in the following solutions: 5 M sulphuric acid, 5 M phosphoric acid and industrial phosphoric acid (containing 5 M phosphoric acid and 0.05% chloride ion) to construct a galvanic cell, in which PANi is cathode while ferrous metal is anode. The results indicate that a PANi electrode with sufficient area can provide corrosion protection to stainless steel in these acidic solutions. A pilot scale coupling experiment was carried out. The results indicate that PANi is a promising material as an electrode for the anodic protection of ferrous metals in acidic solutions in industrial situations.
关键词:
conducting polymer-coatings;corrosion protection;stainless-steel;spectroscopy;passivation;performance;mechanism;behavior;primers;films
F. Lu and WJ. van Ooij( Beijing Institute of Aeronautical Materials
,
P.O. Box 81-5
,
Beijing 100095
,
China)( Department of Materials Science and Engineering
,
University of Cincinnati
,
Cincinnati
,
OH 45221-0012
,
U.S.A.)
金属学报(英文版)
Zn-Al couple's galvanic coeeosion was a serious problem in acdic ainc sulfate solution .In this paper, a new pretreatment or a coating for Al was developed and tested to protect the Al effectively form corrosion when connected to pure Zinc at electroplating potential,and exposed to an acdic sulfate solution.Corrosion measurement techniques(Galvanic corrosion and DC)were used to investigate galvanic corrosion between Al cathode and Zn anode.It was found out that Al alloy purity and electroplating potential have a large effect on galvanic corrsion between Zn-Al couples.EIS,salt spray test and immersion test were performed to evaluate the method for Al cathodes in zinc electrolyte,BTSE silane pretreatment and polyurethane coating displayed better corrosion protection.Calculation showed the Al dissolution rate is small enough for Al cathode to be used in zinc plants.BTSE treatment or BTSE plus polyurethane coating has the best corrosion performance,and willprotect the Al cathode effectively in zinc electrolysis
关键词:
Al-Zn couple
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null
Polymers for Advanced Technologies
A corrosion protection coating from polyimide/polyaniline (PI/PAn) blend was prepared by solution blending and the anti-corrosion property of this coating was studied with electrochemical impedance spectroscopy technique. The results show that PAn can react with PI to form chemical bonds between these two polymers and these bonds keep these two polymers as a miscible system. The corrosion protection property of this coating increases with a growth in the PAn component and an excellent anti-corrosion effect emerges when the PAn content reaches 10-15%. The reason why PAn can improve the anti-corrosion property is that PI/PAn blend can form a dense and non-porous polymer film that would prevent some corrupting components from access to the underlying steel surface. And also, PAn may serve as a corrosion inhibiting agent to scavenge any protons and foster a local basic surface environment. Copyright (C) 2001 John Wiley Sons, Ltd.
关键词:
polyaniline;polyimide;corrosion;EIS
Materials and Corrosion-Werkstoffe Und Korrosion
Galvanic anodic protection (GAP) of stainless steels by doped polypyrrole (PPy) was investigated using chemically synthesized PPy. Separate PPy powder-pressed electrodes with different surface areas were prepared. Electrochemical properties of PPy electrodes were studied by open circuit potentials (OCPs) and potentiostatic polarization. PPy powder-pressed electrodes were coupled with 410-stainless steel electrodes in different concentrations of sulfuric acid solutions, 5 M phosphoric acid solution, and industrial phosphoric acid solution (5 M phosphoric acid + 0.05% chloride ion). Remarkable shift of OCP to the positive direction and sharp decrease of corrosion rate were observed during the coupling experiments, which implies that 410-stainless steel was transferred to passive state. Results also showed that PPy electrode with sufficient surface area can provide corrosion protection to 410-stainless steel electrode in highly corrosive acid solution. Based on the experiment results, GAP provided by PPy and PANi (synthesized under similar conditions) was compared.
关键词:
galvanic anodic protection;organic metal polyaniline;coated;mild-steel;conducting polymers;doped polyaniline;ferrous-metals;carbon-steel;coatings;iron;passivation
