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介绍了镁合金的腐蚀特性、影响镁合金腐蚀的因素以及镁合金腐蚀的类型。镁合金腐蚀的类型有电偶腐蚀、点蚀、丝状腐蚀和高温氧化。综述了腐蚀防护措施为通过研究开发高纯镁合金,应用快速凝固工艺,实施表面处理技术等。镁合金表面技术中的化学转化膜、阳极氧化、微弧氧化及金属镀层等对镁合金的腐蚀防护有很好的作用。 相似文献
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镁合金的腐蚀特性及防护技术 总被引:3,自引:2,他引:1
镁合金作为最轻的金属结构材料,在汽车、3C、国防军工、航空航天等领域具有广阔的应用前景,但耐蚀性较差是其大规模应用的瓶颈。介绍了镁合金的腐蚀机理,包括全面腐蚀、局部腐蚀、电偶腐蚀等,以及影响镁合金耐腐蚀的因素,根据不同介质中的具体腐蚀情况,对影响镁合金腐蚀的三大因素作了重点介绍,从而总结出提高镁合金防腐性能的两个研究方向,一是改善镁合金的本征耐蚀性,即通过优化合金成分,改善镁合金的微观组织等方式提高材料的耐蚀性;二是采用表面防护处理技术,通过表面防护层对基体进行保护,隔离腐蚀介质与基体。然后详细综述了净化合金成分、开发新型耐蚀镁合金、改善镁合金的表层微观组织等提高镁合金本征耐蚀性的方法,以及有机/聚合物、金属/化合物镁合金耐蚀涂层的研究现状。最后指出了镁合金防腐技术研究过程中存在的问题和今后的发展方向。 相似文献
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总结了国内外针对镁合金点蚀的最新研究成果,特别是腐蚀环境和微观结构对镁合金点蚀的萌生和发展的影响规律;介绍了新型微区原位技术在镁合金点蚀研究上的应用,并指出将微区原位技术与传统腐蚀研究方法相结合是揭示镁合金点蚀机理的重要手段。同时,提出了可减缓镁合金点蚀的方法。最后,对未来镁合金点蚀的研究重点和方向进行了分析和展望,以期对解决镁合金点蚀问题起到一定的指导意义。 相似文献
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本文针对可降解吸收的医用镁合金的耐腐蚀性较差、在临床上的应用受到了很大的限制的问题,介绍了3种典型医用镁合金耐腐蚀性能的变化和近几年有关可降解医用镁合金的腐蚀研究进展,总结了研究可降解医用镁合金耐腐蚀性能的实验方法和结果。结论是未来医用镁合金既要充分发挥其可降解吸收的优点,又要把控好在人体服役期间的降解速度。 相似文献
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总结了近年来经剧烈塑性变形加工后的超细晶镁合金的腐蚀与防护研究。镁合金的初始成分可能对剧烈塑性变形加工后样品耐蚀性的变化起主导性作用。对于纯镁及含有铝或稀土等致钝性元素的合金,如AZ系和WE系镁合金,绝大多数剧烈塑性变形加工会促进生成更致密的保护膜,因而可以提升镁合金的耐蚀性。对于不含此类元素的镁合金体系,如Mg-Zn系合金,由于生成了更多的腐蚀微电偶,等通道转角挤压或高压扭转加工引起的第二相颗粒的细化和分布会加速镁合金的腐蚀,但多轴等温锻造可以提升此类合金的耐蚀性,该技术值得更多的关注。在成分相似的情况下,组织的均匀性或者第二相变化情况的影响可能较晶粒尺寸和织构演变的影响更大。对加工后的镁合金进行热处理或者表面改性是进一步提升其耐蚀性的有效手段。相对于粗晶基体,超细晶基体表面改性后的涂层的耐蚀性往往更好,值得更多的研究关注。 相似文献
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A number of magnesium alloys show promise as engine block materials. However, a critical issue for the automotive industry is corrosion of the engine block by the coolant and this could limit the use of magnesium engine blocks. This work assesses the corrosion performance of conventional magnesium alloy AZ91D and a recently developed engine block magnesium alloy AM‐SC1 in several commercial coolants. Immersion testing, hydrogen evolution measurement, galvanic current monitoring and the standard ASTM D1384 test were employed to reveal the corrosion performance of the magnesium alloys subjected to the coolants. The results show that the tested commercial coolants are corrosive to the magnesium alloys in terms of general and galvanic corrosion. The two magnesium alloys exhibited slightly different corrosion resistance to the coolants with AZ91D being more corrosion resistant than AM‐SC1. The corrosivity varied from coolant to coolant. Generally speaking, an organic‐acid based long life coolant was less corrosive to the magnesium alloys than a traditional coolant. Among the studied commercial coolants, Toyota long life coolant appeared to be the most promising one. In addition, it was found that potassium fluoride effectively inhibited corrosion of the magnesium alloys in the studied commercial coolants. Both general and galvanic corrosion rates were significantly decreased by addition of KF, and there were no evident side effects on the other engine block materials, such as copper, solder, brass, steel and aluminium alloys, in terms of their corrosion performance. The ASTM D 1384 test further confirmed these results and suggested that Toyota long life coolant with 1%wt KF addition is a promising coolant for magnesium engine blocks. 相似文献
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The corrosion behaviours of four kinds of rolled magnesium alloys of AZ31, AZ91, AM60 and ZK60 were studied in 1 mol/L sodium chloride solution. The results of EIS and potentiodynamic polarization show that the corrosion resistance of the four materials is ranked as ZK60>AM60>AZ31>AZ91. The corrosion processes of the four magnesium alloys were also analyzed by SEM and energy dispersive spectroscopy(EDS). The results show that the corrosion patterns of the four alloys are localized corrosion and the galvanic couples formed by the second phase particles and the matrix are the main source of the localized corrosion of magnesium alloys. The corrosion resistance of the different magnesium alloys has direct relationship with the concentration of alloying elements and microstructure of magnesium alloys. The ratio of the β phase in AZ91 is higher than that in AZ31 and the β phase can form micro-galvanic cell with the alloy matrix, as a result, the corrosion resistance of AZ31 will be higher than AZ91. The manganese element in AM60 magnesium alloy can form the second phase particle of AlMnFe, which can reduce the Fe content in magnesium alloy matrix, purifying the microstructure of alloy, as a result, the corrosion resistance of AM60 is improved. However, due to the more noble galvanic couples of AlMnFe and matrix, the microscopic corrosion morphology of AM60 is more localized. The zirconium element in ZK60 magnesium alloy can refine grain, form stable compounds with Fe and Si, and purify the composition of alloy, which results in the good corrosion resistance of ZK60 magnesium alloy. 相似文献
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镁合金在大气环境中电偶腐蚀行为及规律的研究 总被引:3,自引:0,他引:3
在北京大气环境下,研究AM60镁合金和不同金属材料(碳钢、不锈钢、黄铜和铝合金)偶接的电偶腐蚀行为规律。研究表明,镁合金作为阳极发生不同程度的电偶腐蚀,通过1a的北京大气环境下的暴露试验后,AM60镁合金的电偶腐蚀效应由强到弱的顺序为:碳钢、黄铜、不锈钢和铝合金,其中镁合金与LY12铝合金偶接的电偶腐蚀效应最小。通过与其它地区室外暴晒的镁合金电偶腐蚀效应的对比,表明环境因素影响着镁合金的电偶腐蚀效应。同时阴极材料、试验时间、试样尺寸(偶接面积)和试验环境都会对镁合金电偶腐蚀效应产生影响。经1a曝晒的AM60镁合金形成了具有保护性的腐蚀产物层阻碍了腐蚀发展。北京地区高自然降尘量导致金属表面湿润时间加大,从而加速了AM60镁合金的电偶腐蚀。采用XRD方法分析表面的腐蚀产物,用金相显微镜和扫描电镜(SEM)观察试样腐蚀后的表面形貌特征和腐蚀产物的结构,并用与之相连的能谱仪分析腐蚀产物中的元素组成。 相似文献