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AZ91D镁合金在大气环境中初期腐蚀行为的研究 总被引:1,自引:1,他引:1
AZ91D镁合金在温度40 ℃和相对湿度100%RH的大气环境中, 其初期大气腐蚀符合指数衰减规律, 在高温高湿环境中促进了AZ91D镁合金大气腐蚀的发展. AZ91D镁合金的大气腐蚀初期腐蚀产物变化规律: 基体上出现点刺状腐蚀产物, 点刺状腐蚀产物长大后形成团刺状的腐蚀产物. 团刺状的腐蚀产物不断长大, 相邻近的团刺状的腐蚀产物聚集交织在一起, 构成疏松的腐蚀产物形貌. 这种疏松的腐蚀产物形貌不具备保护作用, 使得大气腐蚀不断加快. 通过对AZ91D镁合金的腐蚀产物的EDX能谱分析, 并结合对腐蚀产物形貌的观察, 表明在大气腐蚀初期的腐蚀产物主要为: 初期形成的MgO和随后形成更加稳定Mg(OH)2. AZ91D镁合金在β相、划痕和晶界等附近区域容易发生腐蚀. 同时表面残留的污染物(手的汗迹等)区域更加容易发生腐蚀. 相似文献
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研究了集装箱钢板在西沙海洋大气环境中暴露不同阶段的腐蚀行为。采用SEM(EDS)、XRD研究了锈层形貌及成分,采用极化曲线研究了暴露不同阶段的腐蚀电化学行为。通过腐蚀深度测试,建立了腐蚀速率与暴露时间的幂指数关系,结合腐蚀形貌和产物分析,主要的锈蚀产物为γ FeOOH、β FeOOH。Cr和Cu合金元素也参与了锈层的形成,有助于提高锈层的致密性。电化学测试结果表明,耐候钢暴露不同阶段的腐蚀电流,3个月时值最低,6个月随后暴露时间增加,锈层不断增厚,起到对Cl 的阻碍作用,降低腐蚀速率;之后随着曝露时间的增加,锈层出现脱落,腐蚀速率随之增加。 相似文献
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研究了模拟工业酸雨大气条件下低碳钢经干湿循环加速腐蚀实验条件下的锈蚀速度变化。初期锈蚀速度随干湿循环次数的增加而增大,随后转为随干湿循环次数的增加而降低。带锈低碳钢的电化学极化行为表明,干湿循环下的腐蚀产物促进阴极过程,抑制阳极过程。在干湿循环加速腐蚀进程中低碳钢表面铁锈的化学组成、结构变化表现为在锈蚀初期α-FeOOH含量较低,锈层疏松,锈蚀速度呈随干湿循环次数增加而上升趋势;后期随α—FeOOH含量的增加和锈层变得更加致密,腐蚀转变为随干湿循环次数增加而下降。 相似文献
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综述了海洋工程用钢的大气腐蚀行为与耐候钢发展方面的研究,特别是近十余年来国内外的相关成果。首先介绍了钢大气腐蚀的电化学模型,并从耐候钢特殊的锈层结构与合金元素作用两方面论述了耐候钢的锈层保护机制;然后分析了环境因素,包括相对湿度与污染物、光照、锈层损伤等,对耐候钢大气腐蚀行为的影响;最后总结了耐候钢的发展历程以及晶粒尺寸与显微组织等非合金因素在耐候钢发展中的作用,可为新型耐候钢的设计与应用提供指导。 相似文献
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综述近年来耐候钢腐蚀分析评价方法在腐蚀防护及实验观测领域的应用进展情况,重点介绍有关大气暴露腐蚀、室内加速腐蚀以及微区电化学分析评价方法的技术原理及优缺点,并从提高与各种计算机技术联用的角度,展望了耐候钢腐蚀分析评价方法的发展趋势。研究表明:大气暴露腐蚀分为静态和动态腐蚀,室内加速腐蚀方法主要有循环盐雾腐蚀、周期浸润腐蚀和湿热腐蚀等,微区电化学分析评价方法主要包括电子探针EPMA、扫描开尔文探针SKP、扫描电化学显微镜SECM、扫描振动电极SVET等;其中微区电化学分析评价技术的发展,促进了从微观尺度对耐候钢大气腐蚀过程机理及防护理论研究工作的开展,提高了对腐蚀的原位、在线观测的能力。 相似文献
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针对沿海地区大型钢桥建设对于桥梁钢耐大气腐蚀性的高要求,将以含有Cu、Ni抗腐蚀元素的耐候钢为研究对象,通过干湿周浸润加速腐蚀实验、失重分析、电化学测试等方法,分析海洋大气环境下桥梁钢的耐大气腐蚀性。实验结果表明:Cu、Ni含量不同的4种桥梁钢耐大气腐蚀性能存在一定差异,Cu、Ni合金元素可增强桥梁钢的耐腐蚀性、降低腐蚀深度与速率,且Cu含量与钢基体中的自腐蚀电位、极化电阻成正比,对于钢基体的初期腐蚀速率及大气腐蚀发展趋势均有显著减弱功能。 相似文献
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Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel 总被引:3,自引:0,他引:3
The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM) and Raman spectroscopy. The results showed that two different shapes of corrosion products, that is, ring and chain, were formed in the initial stage of corrosion. MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites. The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite (γ-Fe2O2 ) transformed from lepidocrocite. The chain-type products were goethite (α-FeOOH). A formation mechanism of the corrosion products is proposed. 相似文献
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The weathering steels are prone to pitting corrosion in an environment containing chloride ions.The pitting behavior of Cu-P-RE weathering steels and its effect on the corrosion resistance of steels were investigated by multifarious analytical techniques,such as field emission-scanning electron microscopy(FE-SEM),electron probe microanalysis(EPMA),scanning Kelvin probe force microscopy(SKPFM),electrochemical workstation and a series of immersion tests.The results show that the original stripshap... 相似文献
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《钢铁研究学报(英文版)》2016,(10):1061-1070
Q235 carbon steel and Q450 weathering steel were exposed to the hot and dry environment of Turpan, China for three years.The corrosion rates of both steels were calculated and compared.The morphologies of the rust layer products were observed by optical microscopy and scanning electron microscopy.Analyses of the rust layers were performed by X-ray photoelectron spectroscopy,X-ray powder diffraction,and Raman spectroscopy,and anal-ysis results indicate that the compositions of rust are main iron rich oxide such as FeOOH,Fe3 O4 ,and Fe2 O3 .The iron oxide layer content proportion was calculated through a semi-quantitative algorithm.The resistance elements (Cr,Ni,and Cu)enhanced the resistance properties of the Q450 weathering steel matrix.Moreover,the resistance elements increased the proportion of goethite crystals in the corroded rust layer. 相似文献
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The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel.The rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion test of dry-wet cyclic immersion.Furthermore XRD were used to measure and analyze the rust layers.The initial corrosion processes below thin water film were observed and the changes of micro-area pH value were measured.The results are as follows:The corrosion processes of P-RE weathering steel are obviously different from those of carbon steel.The surface of P-RE weathering steel rapidly forms α-FeOOH and the micro-area pH value is above 5.4 during the initial corrosion period.While the component of the rust layer for the carbon steel is mainly Fe3O4 and the micro-area pH value is below 3.8. 相似文献
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CHEN Xiaoping WANG Xiangdong LIU Qingyou MI Fengyi CHEN Ying LI Yusu 《钢铁研究学报(英文版)》2010,17(9):69-72
The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel. The Rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion test of dry-wet cyclic immersion. Furthermore XRD were used to measure and analyze the rust layers. The initial corrosion processes below thin water film were observed and the changes of micro-area PH value were measured. The results are as follows: The corrosion processes are obviously different between P-RE weathering steel and carbon steel. The surface of P-RE weathering steel rapidly forms α-FeOOH and the micro-area PH value is above 5.4 during the initial corrosion period. While the component of the rust layer for the carbon steel is mainly Fe3O4 and the micro-area PH value is below 3.8. 相似文献
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综述了海洋工程用钢的大气腐蚀行为与耐候钢发展方面的研究,特别是近十余年来国内外的相关成果。首先介绍了钢大气腐蚀的电化学模型,并从耐候钢特殊的锈层结构与合金元素作用两方面论述了耐候钢的锈层保护机制;然后分析了环境因素,包括相对湿度与污染物、光照、锈层损伤等,对耐候钢大气腐蚀行为的影响;最后总结了耐候钢的发展历程以及晶粒尺寸与显微组织等非合金因素在耐候钢发展中的作用,可为新型耐候钢的设计与应用提供指导。 相似文献