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1.
By the NSS test and the test in SO2 gas atmosphere and detecting the φcorr-t curves, Rp-t curves and the cyclic voltammogram curves, the corrosion resistance of the electroplated Zn-Co alloy coating was studied. The corrosion resistance of the electroplated Zn-Co alloy coating is three times higher than that of the galvanized coating. Because the corrosion resistance of the Zn-Co alloy coating is especially remarkable in SO2 gas atmosphere, it is particularly fit to be used as a protective coating in industrial atmosphere. The reason why the Zn-Co alloy coating has such a high corrosion resistance is that its corrosive product has a comparatively great role in depressing the corrosive process. 相似文献
2.
2195 aluminum-lithium alloy was widely applied in the aviation and aerospace industry, but it is highly susceptible to pitting and intergranular corrosion undergoing sever corrosive circumstance and moisture atmosphere. To solve this problem and consequently to prolong its service life, a multi-step-heating-rate(MSRC) process was carried out. Investigations were carried out to find the effect of the MSRC process on the alloys corrosion resistance. It is found that the MSRC process is more favorable for the uniform phase precipitation by comparing the corrosion resistance of samples treated by traditional heat treatments. The potential difference between phases can be reduced and intergranular corrosion is able to be prohibited efficiently. Besides, the rare earth infiltration is beneficial to improving the corrosion resistance. As heating time increases, the corrosion resistance declines gradually, samples treated by artificial aging and solid solution also exhibit a better corrosion resistance. 相似文献
3.
LIANG Chenghao CHEN Bangyi CHEN Wan and WANG Hua State Key laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian China 《稀有金属(英文版)》2005,24(3)
1 IntroductionThe shape memory alloy (SMA) is a novel func-tional material, which combines recognition behav-ior with driving capability. Among SMAs, the Ti-NiSMA possesses shape memory effect, superelastic,well wear resistance, and low elastic modulus. A… 相似文献
4.
CHEN Fei ) ZHOU Hai) CAI Suo) LV Fanxiu) and LI Chengming) ) College of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing China ) Materials Science Engineering School University of Science Technology Beijing Beijing China 《稀有金属(英文版)》2007,26(2):142-146
Magnesium alloys have a wide range of applications in industry; however, their corrosion resistance, wear resistance, and hardness are rather poor, which limit their applications. Ti ion was implanted into the AZ31 magnesium alloy surface by metal vapor vacuum arc (MEVVA) implanter. This metal arc ion source has a broad beam and high current capabilities. The implantation energy was fixed at 45 keV and the dose was at 9 × 1017 cm?2. Through ion implantation, Ti ion implantation layer with approximately 900 nm in thickness was directly formed on the surface of AZ31 magnesium alloy, by which its surface property greatly improved. The chemical states of some typical elements of the ion implantation layer were analyzed by means of X-ray photoelectron spectroscopy (XPS), while the cross sectional morphology of the ion im-plantation layer and the phase structure were observed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The property of corrosion resistance of the Ti ion implanted layer was studied by the CS300P electrochemistry corrosion workstation in 3.5% NaCl solution. The results showed that the property of corrosion resistance was enhanced remarkably, while the corrosion velocity was obviously slowed down. 相似文献
5.
The corrosion and high-temperature oxidation characteristics of AM60 Mg alloy in different environments were investigated by immersion test, electrochemical polarizing analysis and differential thermal analysis (DTA)/thermo gravimetric (TG) experiments. The influence of aging heat treatment on the corrosion resistance of AM60 Mg alloy was studied. AM60 Mg alloy shows better corrosion resistance in sea water than in 3.5%(mass fraction) NaCI solution. The corrosion resistance after aging for 24 h is better than that of both as-cast and aging for 48 h. Corrosion resistance of Mg alloy is controlled by microstructure, composition of a-matrix. Precipitation offl phase along the grain boundaries acts as a barrier that decreases corrosion rate, whereas the decrease of aluminum content of a phase causes an increase in the corrosion rate. The DTA and TG curves of heating process in air are characterized with combustion after 590℃. When heated in helium, the curves show two endothermic peaks and a remarkable evaporation of magnesium. As for isothermal DTA and TG experiments, mass increment caused by oxidation does not happen till 520 ℃. 相似文献
6.
《腐蚀工程科学与技术》2013,48(6):719-723
AbstractThe superlight Mg–Li alloys exhibit good formability but poor corrosion resistance due to the alloying of lithium. In this paper, the corrosion behaviour of Mg–8·8Li alloy was investigated by electrochemical measurements, corrosion morphology observations and weight loss determination. The results indicate that Mg–8·8Li alloy displays worse corrosion resistance than AZ91D alloy in the early stages of corrosion. However, the corrosion resistance of AZ91D alloy declines and becomes worse than Mg–8·8Li alloy with increasing exposure time. In addition, it is found that a 250°C annealing treatment has a detrimental effect on the corrosion resistance of Mg–8·8Li alloy. 相似文献
7.
LIANG Chenghao CHEN Bangyi CHEN Wan WANG Hua 《稀有金属(英文版)》2005,24(3):252-256
The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole was investigated by salt spraying test and electrochemical methods in artificial Ringer's solution. The results showed that after benzotriazole passivation, the corrosion resistance of the Cu-Zn-Al shape memory alloy was improved evidently. The anodic polarization current density of the passivated alloy decreased, the mass loss reduced, the anodic passivation accelerated, the anodic active dissolution was inhibited effectively, and the surface tarnishing was reswained. Infrared reflection spectrum test showed that Cu(Ⅰ)-benzotriazole or Cu(Ⅱ)-benzotriazole complex layer was formed on the surface of the Cu-Zn-Al shape memory alloy after passivation. This layer appeared plane, well adhesion, and presented homogeneous golden metallic luster. The corrosion resistance of the Cu-Zn-Al shape memory alloy passivated by benzotriazole is improved for the formation of an electrochemical stable baffle layer on passivated surface. This layer separates the metal substrate from the outside corrosion medium effectively and retards the corrosion process of dezincification. 相似文献
8.
CHENG Ying-liang WU Hai-lan CHEN Zhen-hua WANG Hui-min LI Ling-ling 《中国有色金属学会会刊》2006,16(5):1086-1091
1 Introduction Magnesium alloys are relatively light structural materials, with excellent physical and mechanical properties,such as low densityand high specific strength, excellent castability and good machinability. These properties make them ideal cand… 相似文献
9.
Corrosion resistance of electrodeposited RE-Ni-W-P-SiC-PTFE composite coating in phosphoric and ferric chloride 总被引:8,自引:0,他引:8
1 Introduction During process, store and use in various kinds of environment, corrosion, wear, fatigue and rupture may happen in all materials and products. These kinds of failure and damages widely occur in industries, causing enormous losses to nationa… 相似文献
10.
1 Introduction Cu alloy has become a kind of important materials for ocean construction as its excellent anti-corrosion performance. Though this kind of alloy has been applied for a long time, it often undertakes serious corrosion, low strength and leakag… 相似文献
11.
Corrosion behavior of an Al-6Mg-Sc-Zr alloy 总被引:4,自引:0,他引:4
XU Guangxin TAO Binwu LIU Jianhua LI Songmei 《稀有金属(英文版)》2005,24(3):246-251
The corrosion behavior of an Al-6Mg-Sc-Zr alloy was studied and compared with that of an Al-6Mg-Zr alloy. The addition of scandium into the Al-6Mg-Zr alloy reduced the susceptibility to exfoliation corrosion. By using the constant load tensile method in a 3.5 wt.% NaCl solution, the resistance to SCC of the Al-6Mg-Sc-Zr alloy was higher than that of the Al-6Mg-Zr alloy. When the specimens were not applied with an anodic current, the Al-6Mg-Sc-Zr alloy was resistance to SCC and no brittle cracking was found on the fracture surface. When an anodic current was applied, the Al-6Mg-Sc-Zr alloy specimens failed as a result of accelerated corrosion rather than SCC. It was believed that the addition of scandium re- sulted in (Al3Sc, Zr) particles that greatly refined grains and promoted the formation of homogeneous discontinuous distribution of β-phase in the alloy base, which much contributed to good corrosion resistance of the Al-6Mg-Sc-Zr alloy. 相似文献
12.
Optimization of parameters and study of joint microstructure of resistance spot welding of magnesium alloy 总被引:1,自引:0,他引:1
Experimental investigations on the DC spot welding of Mg alloy AZ31B are presented. Experiments are carried out to study the influence of spot welding parameters ( electrode force, welding heat input and welding time) on the tensile shear load and the diameter of nugget, based on an orthogonal test and analysis method. The optimum parameters are as follows: electrode force is 2 000 N, welding heat input is 80% and welding time is 6 cycles. The microstrueture of spot weld is single fine equiaxed crystals in the nugget, of which the structure is β-Mg17Al12 precipitated on α-Mg boundaries induced by nonequilibrium freezing. And the surface condition of the workpiece has great influence on the joint quality. 相似文献
13.
Ni–W alloys with different tungsten content and grain size under 50?nm were prepared by means of pulse current and pulse reverse current electrodeposition. The alloys were analysed using various methods (EDX, SEM and XRD). The electrochemical (open circuit potential, corrosion current density) and tribological (coefficient of friction and wear rate) characteristics were evaluated. Tungsten content in the alloys influences grain size which is responsible for the quality of the coating and the corrosion and tribological properties. When the content of tungsten in the Ni fcc lattice is lower than 5?at.-% W, the corrosion resistance increases. When the content of W is higher than 5?at.-%, the corrosion resistance decreases. The relationship between tribological properties and W content is the reverse of that experienced with corrosion properties. 相似文献
14.
The corrosion behavior of B30 Cu-Ni alloy in a sterile seawater and a SRB solution was investigated. The results show that the corrosion potential of specimen in the SRB solution is much lower than that in the sterile seawater. The polarization resistance of specimen in the SRB solution decreases quickly after a period immersion and becomes much lower than that in the sterile seawater. It is concluded that the SRB accelerates the corrosion process of B30 Cu-Ni alloy greatly. An anti-corrosion electroless Ni-P coating was produced and applied to the alloy. The results show that specimens coated with Ni-P plating exhibit favorable corrosion resistance property in SRB solution. Severe pitting corrosion appears on the uncoated specimens in the SRB solution when the coated specimens are still in good condition. The anti-corrosion mechanism of Ni-P plating was analyzed. It is concluded that coating the B30 Cu-Ni alloy with electroless Ni-P plating is an effective technique against the attack of SRB in marine environment. 相似文献
15.
The corrosion properties of AZ31 magnesium alloys were studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy(E1S) techniques, meanwhile, the protective properties of two environmentally protective types of chemical conversion layers and anodized coatings of AZ31 magnesium alloys were also discussed. The component of chemical conversion bath is NaH2PO4·12H2O 20 g/L, H3PO4 7.4 mL/L, NaNO2 3 g/L, Zn(NO3)2·6H2O 5 g/L and NaF 1 g/L, and components of the anodization bath is Na2SiO3 60 g/L, C6H5Na3O7·2H2O 50 g/L, KOH 100 g/L and Na2B4O7·2H2O 20 g/L. The results show that the corrosion resistance of AZ31 magnesium increases with the increase of pH value of the corrosive medium. For the chemical conversion layer acquired at 80 ℃, 10 min is the best processing time and the charge transfer resistance of the chemical conversion layer is enhanced nearly by 10 times. The optimum processing time for the anodization of AZ31 is 60 min, the charge transfer resistance value of the anodized sample at the early immersion stage is nearly 26 times of that of the blank sample and the corrosion type of the anodized samples is pitting. 相似文献
16.
The behavior of Cu-Ni-Ag-Al alloy used as anode for aluminum electrolysis was directly visualized in a two-compartment see-through cell during electrolysis, and its performances were tested at 850℃ in acidic electrolyte molten salts consisting of 39.3%NaF-43.7%AlF3-8%NaCl-5?F2-4%Al2O3 for 40 h in a laboratory cell. The results show that nascent oxygen oxidizes the anodic surface to form oxide film at the beginning of electrolysis. X-ray diffraction analysis of alloy surface show that the oxide film on the anodic surface consists of CuO, NiO, Al2O3,CuAl2O4 and NiAl2O4. However, SEM image shows the oxide film is porous, loose and easy to fall into electrolyte and to contaminate aluminum. The corrosion mechanism of metal anodes was analyzed. 相似文献
17.
0 IntroductionFe C Crsurfacingalloysarewidelyusedinindustries ,mainlyduetotheirhighwearresistance .Underconditionsofabrasiveenvironments,theeffectofcompositionandmi crostructureontheabrasionresistancehasbeenextensivelystudied[1~4 ] .TheauthorsalsoevaluatederosionresistanceofFe C Crweldsurfacinglayersbecausealargenumberofma chinecomponentssufferedfromsevereerosion ,suchasper cussiveplate ,rotorbladeandexhaustpipe ,etc .However,thelowcrackresistanceofFe C Crweldsurfacinglayershasbecomethei… 相似文献
18.
Mariana X. Milagre Uyime Donatus Caruline S. C. Machado João Victor S. Araujo Rejane Maria P. da Silva Bárbara Victoria G. de Viveiros 《腐蚀工程科学与技术》2013,48(5):402-412
ABSTRACTIn this study, the corrosion mechanisms of the AA2024-T3 and the AA2098-T351 were investigated and compared using various electrochemical techniques in 0.005?mol?L?1 NaCl solution. The severe type of corrosion in the AA2098-T351 was intragranular attack (IGA) although trenching and pitting related to the constituent particles were seen. On the other hand, the AA2024-T3 exhibited severe localised corrosion associated with micrometric constituent particles, and its propagation was via grain boundaries leading to intergranular corrosion (IGC). Electrochemical techniques showed that the corrosion reaction in both alloys was controlled by diffusion. The non-uniform current distribution in both alloys showed that EIS was not a proper technique for comparing the corrosion resistance of the alloys. However, local electrochemical techniques were useful for the evaluation of the corrosion resistance of the alloys. 相似文献
19.
We continue to inform readers about the activities of the Technical Committee Corrosion of metals and alloys of the International Organization for Standardization (ISO/TC 156). The work program of the Committee for 2000 is given. The scheme of the participation of specialists in corrosion in the activity of the Committee, as well as the procedure of submitting draft standards for the development as International standards, is shown. 相似文献
20.
1 INTRODUCTIONBecauseofitshighmechanicalperformanceandlowdensity ,LY12alloy(USAA2 0 2 4 )iswidelyusedintheaircraftindustryfornumerousapplicationssuchasfuselage ,doorskin ,dorsalfinandtrailingedgepanels .Nevertheless ,thisalloycaneasilybeaffectedbylocalizedcorrosion ,suchaspittingandexfoliation ,especiallyinchloridecontainingenvironment .Thislocalizedattackcanresultinprematurebreakdownofstructuralparts[1] .Inordertominimizethelocalizedattackonthealuminumalloy ,thecorrosionmecha nismshou… 相似文献