共查询到19条相似文献,搜索用时 97 毫秒
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采用金相显微镜、扫描电镜等检测手段对Zr-4合金板材微观组织中出现的异常条线现象进行研究,分析了Zr-4合金板材条线现象的本质、成因以及对其使用性能的影响。研究表明,Zr-4合金板材微观组织中出现的异常条线现象并不是裂纹、夹杂、氢化物、织构等缺陷的反映,而是由沿轧向成带状分布的粗大Zr(Fe,Cr)2第二相更容易遭受腐蚀造成的。此外,Zr-4合金板材微观组织中出现的条线现象对均匀腐蚀性能无明显影响,但带状分布的粗大第二相不利于板材的抗疖状腐蚀,并且会对板材的弯曲性能产生影响。 相似文献
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不同时效态7150铝合金的剥蚀根源 总被引:1,自引:0,他引:1
根据波音737飞机龙骨梁下缘条更换修理BS540.6位置处T6态和T77态7150铝合金结构腐蚀规律和采用TEM获得的合金晶界微观组织结构,研究了T6态和T77态7150铝合金剥蚀根源。结果表明:T77态比T6态抗剥蚀性能好得多。T6态晶界η析出相分布连续,基体边缘无明显PFZ;T77态基体边缘PFZ连续分布,晶界η析出相不连续。T6态和T77态的剥蚀根源分别为晶界η析出相和PFZ作为阳极被腐蚀溶解。 相似文献
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采用金相显微镜、电位计、EPMA和SWAAT腐蚀试验等手段,研究了两种不同构成的冷凝器折叠管料钎焊后的微观组织、电极电位、元素扩散和耐腐蚀性能。结果表明,与冷凝器三层折叠管料相比,带1050合金中间层的冷凝器四层折叠管料钎焊后外侧钎焊层/芯材电位差比较大,有着良好的SWAAT外部腐蚀性能,SWAAT 40 d最大腐蚀深度未超过管料厚度的30%;1050合金中间层能有效地阻碍冷凝器四层折叠管料芯材中的Cu扩散,外侧钎焊层+1050合金中间层可以对芯材起到较好的牺牲阳极保护作用。 相似文献
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P. K. Poulose J. E. Morral A. J. McEvily 《Metallurgical and Materials Transactions B》1974,5(6):1393-1400
The fracture kinetics of Al-5.5 Zn-2.5 Mg alloys submersed in 3 pct NaCl-H2O solutions were varied by heat treatment. The steady state velocity, on a plot of velocity vs stress intensity, was compared
with microstructure and it was found to be inversely proportional to the volume of MgZn2 in the grain boundary. This behavior suggests that grain boundary precipitates can act as sacrificial anodes to retard intergranular
stress corrosion cracking.
Formerly Graduate Student at the University of Connecticut 相似文献
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对热喷涂复合牺牲阳极在混凝土中的性能进行了测试,研究发现在实验所考察的条件下所研究的热喷涂复合牺牲阳极体系对钢筋都有很好的保护作用,并且喷镁合金复合阳极的极化值最大,喷铝合金复合阳极次之,喷锌合金复合阳极极化值最小。热喷涂锌合金比同牌号的熔铸锌合金有更大的输出电流,在混凝土中热喷涂复合阳极比熔铸阳极有更负的自然腐蚀电位和更大的交换电流密度。金相结构分析发现喷涂锌合金阳极是一种多孔的疏松结构,它的晶粒细小,晶界多,晶界间存在孔隙,这种结构使得热喷涂阳极具有更好的牺牲阳极电化学性能。 相似文献
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采用普通纯镁为原料制备了Mg-Mn牺牲阳极,探讨了水淬温度和时间对镁合金牺牲阳极的电化学性能和晶粒大小的影响。结果表明,在30℃的水中水淬4分钟后,得到的镁合金牺牲阳极的晶粒相对较小且电流效率相对较高。 相似文献
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Novel Al-Sn-Bi anodes with and without lanthanum (La) were prepared.To evaluate the corrosion properties of the anodes,constant current and dynamic loop tests were carried out to determine its efficiency and corrosion rate.Optical microscopy (OM),transmission electron microscopy (TEM) and energy spectrum analysis techniques were used to examine and analyze microstructure and corrosion behavior of the specimens.The result showed that the Al-Sn-Bi anodes with La additions revealed higher current efficiency an... 相似文献
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H. Xiao R. Hovland S. Rolseth J. Thonstad 《Metallurgical and Materials Transactions B》1996,27(2):185-193
The corrosion rates of inert anodes based on tin oxide and nickel ferrite cermet materials were studied as a function of some operating parameters. To reach a better understanding of the corrosion mechanism, the behavior of the anodes was observed under some specific conditions, such as in pure cryolite, at high current densities, at different potentials, and at varying cathode surface areas. It was confirmed that low alumina concentrations led to catastrophic corrosion of the anodes and that high current densities and high as well as low NaF/AlF3 molar ratios were also detrimental. The corrosion rate of tin oxide based anodes showed a minimum (so-called “normal corrosion”) at anodic potentials of 2.2 to 2.4 V with respect to aluminum. The normal corrosion is due to chemical dissolution of the anode material and reduction of the corrosion products into the cathode metal. The corrosion rate increased with increasing cathode surface area. At potentials higher than ~2.5 V, the anodes showed catastrophic corrosion. Catastrophic corrosion can be ascribed to decomposition of the anode material by depletion of alumina at the anode surface provoked by low bulk concentration of alumina and/or high current density. 相似文献
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ZnFe2O4-based inert anodes were made to conduct the aluminum electrolysis tests. The corrosion behaviors of the inert anodes were examined and discussed. Experiment results prove that: (1) ZnFe2O4-based inert anodes are good corrosion resistant to AlF3-NaF-Al2O3 melts under the conditions of anodic polarization; (2) High anodic current density(>1.5 A·cm-2), high alumina concentration and low ratio of NaF/AlF3 in the molten salts will be the most important conditions for using inert anode. 相似文献