材料期刊网

Recent Advances of Laser Coating Technology in China

LIANG Yong LI Ruiguo Institute of Metal Research , Academia Sinica , Shenyang 110015 , ChinaInstitute of Corrosion and Protection of Metals , Aademia Sinica , Shenyang , 110015 , China

材料科学技术（英文）

Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.

关键词: laser , null , null , null , null

The use of doped polyaniline as an electrode in the galvanic anodic protection of ferrous metals in industrial acid solutions

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

CORROSION PROTECTION OF Al CATHODES IN ZINC ELECTROLYSIS

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 , null

Corrosion behavior of metals or alloys with a solid NaCl deposit in wet oxygen at medium temperature

Science China-Technological Sciences

The corrosion of metals or alloys under solid NaCl deposit in wet oxygen (water vapor and oxygen) at medium temperature 400-700A degrees C causes serious damage and has received considerable attention in recent years. Series of mechanistic studies have revealed synergistic interactions between solid NaCl and water vapor, which accelerates the corrosion process. In addition, the overall corrosion process comprises both chemical reactions (oxidation) and electrochemical reactions and their mutual interactions depend on the system of interest. Interestingly, the wet oxygen environment was found to modify the reactions of the element Cr, which plays a useful role in corrosion protection in this special environment.

关键词: synergistic effect;NaCl deposit;water vapor;electrochemical reactions;oxide hydroxide evaporation;plus water-vapor;ni-cr alloys;fe-cr;electrochemical impedance;pure cr;oxidation;chromium;k38g;500-700-degrees-c

Preparation and EIS studies on polyimide/polyaniline blend film for corrosion protection

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

Corrosion protection of stainless steel by separate polypyrrole electrode in acid solutions

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

Adsorption behaviour of Schiff base and corrosion protection of resulting films to copper substrate

Corrosion Science

Self-assembled (SA) films of Schiff base were prepared on the copper surface. The corrosion protection abilities of SA films in chloride solution were evaluated using electrochemical impedance spectroscopy and polarization curves. A subsequent adsorption of 1-dodecanethiol on the original SA films of Schiff base improved significantly the protection ability to the copper substrate. The behavior of Schiff base adsorption on copper surface and subsequent adsorption of 1-dodecanethiol was probed by X-ray photoelectron spectroscopy. It was found that copper exists mainly in Cu(I) state in the SA films of Schiff base, and the thiol molecules subsequently adsorbed was bonded directly on copper surface rather than physisorbed on the previous SA films. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词: self-assembly;Schiff base;copper corrosion;alkanethiol;self-assembled monolayers;hydrochloric-acid solution;gold;alkanethiols;impedance;surfaces;electrodissolution;dissolution;mechanisms;kinetics

A study on cathodic protection against crevice corrosion in dilute NaCl solutions

Corrosion Science

Potential and current distributions in a cathodically protected crevice between a simulated coating and segmented mild steel electrodes were measured in dilute NaCl solutions. The distributions became more uniform with time due to an increase in solution conductivity and depletion of dissolved oxygen in the crevice. Generally, a negative shift of control potential and an increase in initial solution conductivity and crevice thickness resulted in a higher polarization level on the steel. However, if the control potential is too negative, the polarization level may be lower than that under a suitable control potential because of hydrogen evolution. On the basis of these results, a mechanism of cathodic protection against crevice corrosion in high-resistivity environments was proposed. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词: cathodic protection;crevice corrosion;potential distribution;current;distribution;mild steel;dilute NaCl solution;coatings

Corrosion Behavior and Protection Efficiency of 2024Al and SiCp2024Al Metal Matrix Composite

Chunlin HE , Changsheng LIU , Fengqin LI , Qingkui CAI , Zhiming SHI , Liqing CHEN , Jing BI

材料科学技术（英文）

The corrosion resistance of 2024 Al and SiC particle reinforced 2024 Al metal matrix composite (SiCp/2024Al MMC) in 3.5% NaCl solution was investigated with electrochemical method and immersion test, and the corrosion protection of sulfuric acid anodized coatings on both materials was evaluated by electrochemical impedance spectroscopy. The results showed that the SiCp/2024Al MMC is more susceptible to corrosion than its matrix alloy in 3.5% NaCl. For 2024Al, the anodized coating provides excellent corrosion resistance to 3.5% NaCl.The anodized coating on the SiCp/2024Al provides satisfactory corrosion protection, but it is not as effective as that for 2024Al because the structure of the anodized layer is affected by the SiC particulates.

关键词: 2024 Al , null , null , null

Corrosion protection of aluminium alloy 2024-T3 in 0.05 M NaCl by cerium cinnamate

Corrosion Science

The corrosion protection of AA 2024-T3 in 0.05 M NaCl by cerium cinnamate has been studied. Polarization measurements demonstrate that cerium cinnamate is markedly effective for suppressing anodic process of the alloy corrosion during the initial 72 h of immersion. The protection mechanism during the immersion period appears to involve two stages: the deposition of cerium cinnamate, and then hydrolysis of cerium ions forming a cerium oxide/hydroxide, prevailing over the foregoing deposition. This study also elucidates the inhibition effect of cerium cinnamate on the early corrosion attack occurred from the second phase particles by X-ray photoelectron spectroscopy and electron-probe microanalysis. (C) 2011 Elsevier Ltd. All rights reserved.

关键词: Alloy;Rare earth elements;EIS;XPS;Neutral inhibition;chromate conversion coatings;hydroxy carboxylic-acids;pitting;corrosion;galvanized steel;amino-acids;inhibition;xps;al;polymer;salts