共查询到19条相似文献,搜索用时 179 毫秒
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钢芯铝绞导线大气腐蚀产物层的结构及腐蚀机理 总被引:2,自引:0,他引:2
在模拟大气腐蚀环境中,采用干/湿NaHSO3+NaCl水溶液盐雾试验研究钢芯铝绞(ACSR)导线腐蚀产物的相组成及腐蚀层结构,讨论其腐蚀机理。结果表明:ACSR导线中单股铝线或镀锌钢芯线的腐蚀主要表现为点蚀,腐蚀产物组成复杂,主要为锌和铝的氢氧化物、硫酸盐与氯化物的复式盐;在腐蚀初期,内外层铝股线及钢芯线表面镀锌层开始形成点蚀坑,逐步形成连续的腐蚀层;由于镀锌层和内层铝股线之间构成原电池,因为牺牲阳极效应,镀锌层腐蚀速率最大;而内层铝股线受到保护,腐蚀速率最小,外层铝股线腐蚀速率居中。 相似文献
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为解决发电机定子槽的异常升温现象,利用扫描电镜(SEM)、能谱仪(EDS)和红外光谱仪(FTIR)对定冷水系统不明异物进行了表征分析;同时采用原子吸收光谱仪(AAS)对定冷水水质进行了测定.结果表明,在磁场作用下腐蚀产物氧化铜和定冷水系统中的其他异物在空芯铜导线内沉积结垢,堵塞了空芯铜导线,从而使定子线圈槽出现异常升温现象.最后,分析了空芯铜导线的腐蚀机理并提出了解决的方法. 相似文献
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利用扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪和离子分析,研究了乡村大气环境中变电站端子箱中铜导线腐蚀失效的原因。结果表明,导线外号码筒溶解出的Cl~-加速了铜导线的腐蚀,是导致铜导线腐蚀失效的重要原因。环境中高的空气湿度是导致铜导线腐蚀的另一个关键因素。建议更换已失效铜导线,采用不溶出有害性离子材质的号码筒,并严格控制端子箱内湿度。 相似文献
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材质为316L不锈钢的半成品柴油输送管道在水平段底部出现快速腐蚀,9个月出现5次泄露。通过宏观分析、化学成分检测、力学性能测试、金相分析、腐蚀产物物相分析、腐蚀介质有害相分析、腐蚀产物分析等方法,对管道失效原因进行分析。结果表明:不锈钢管线腐蚀属于氧腐蚀及点蚀;氧化铁等腐蚀产物或杂质随介质在管线底部流动,对管线底部形成线状冲刷磨损,破坏了钝化膜的保护作用,造成管线底部率先腐蚀;腐蚀环境中Cl-极易破坏不锈钢表面的钝化膜,形成坑蚀,成为孔蚀延伸的活性中心。 相似文献
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用旋转挂片失重实验、电化学实验、水质分析、材质分析和腐蚀产物的XRD分析等方法,对某火电厂Q235取水管道腐蚀穿孔原因进行了分析.结果表明:天然水中溶解性杂质及腐蚀产物在管内表面的沉积形成了氧浓差电池,发展成闭塞电池后加剧了沉积物下的腐蚀,直至穿孔.
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Reactive materials such as titanium and tantalum are not suitable for the manufacture of pure and corrosion-resistant layers
by atmospheric spraying processes, and thus are normally processed by vacuum plasma spraying. However, because of the large
specific area of the feedstock, large amounts of previously adsorbed oxygen and nitrogen are included in the coating, often
resulting in unsatisfactory corrosion behavior. This can be avoided by vacuum arc spraying using a single wire. The spraying
material is a cathodic poled wire that is led without contact through a nonconsumable, water-cooled nozzle. The wire is melted
by a high-frequency arc that burns between the wire and the nozzle. The process gas (argon) at-omizes the wire and accelerates
the particles onto the component being coated. The process parameters strongly influence the stability of the process and
the resulting microstructure of the deposit. 相似文献
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采用丝束电极研究金属的缝隙腐蚀* 总被引:6,自引:0,他引:6
钟庆东 《中国腐蚀与防护学报》1999,19(3):189-192
采用丝束电极研究了铜在5%NaCl介质中的缝隙腐蚀行为。研究表明,铜发生缝隙腐蚀的过程中,缝隙内金属的腐蚀电位分布是不均匀的,不均匀的程度相差达数十毫伏。在缝隙腐蚀的初期,缝隙内金属腐蚀电位随着缝隙腐蚀的发生逐渐正移。随着缝隙腐蚀程度的加深,缝隙内金属的腐蚀电位发生负移,且逐渐均匀分布。这一过程与经典的金属缝隙腐蚀机理相吻合。 相似文献
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P. S. Mohanty A. D. Roche R. K. Guduru V. Varadaraajan 《Journal of Thermal Spray Technology》2010,19(1-2):484-494
Oxide dispersion strengthened alloys (ODS), although not commonly used in coating applications, have long been used for high-temperature structural applications due to their superior creep properties. In this paper, we present the design, synthesis, and characterization of a new class of functionally engineered high-temperature coatings in which ultrafine oxide particulates are dispersed in the matrix alloy to achieve superior creep resistance along with improved high-temperature corrosion and erosion resistance. These coatings were fabricated using a novel technique called “hybrid spray process”. Hybrid spray technique combines arc spray and high-velocity oxy fuel (HVOF) spray processes; the metallic matrix alloys are fused by the wire arcing component of the process, whereas the ultrafine particles are synthesized in-flight by the HVOF component from liquid precursors. These particulate dispersed high-temperature composite coatings were fabricated using liquid precursors for SiO2, Cr2O3, Al2O3, and wire feed stock of 55/45 NiCr, in one step. The coatings were then characterized using electron microscopy (SEM/TEM) and thermogravimetric analysis (TGA). High-temperature erosion, oxidation, and corrosion performance of these coatings were also evaluated and compared with 304 stainless steel, arc sprayed NiCr coatings as well as Alloy 625 overlay cladding. The hybrid spray process produced dense coatings with uniform dispersion of the ultrafine oxide particles. Further, these coatings also demonstrated superior corrosion, erosion, and oxidation resistance; SiO2 particulate dispersion being most effective in terms of high-temperature corrosion resistance. 相似文献
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为探索12 mm厚DH36船用耐蚀钢对接用光纤激光-MIG复合焊接工艺,分析了四种不同送丝速度对接头成形、微观组织、拉伸性能及腐蚀性能的影响. 结果表明,在送丝速度为8.5 m/min时可获得成形优良的接头,随着送丝速度的增加,电弧区和激光区焊缝的熔宽均增加.焊缝区主要由针状铁素体、先共析铁素体和一定量的贝氏体组成,送丝速度对针状铁素体的形态和数量有显著的影响.增加送丝速度对接头抗拉强度的影响不大,但减小了断后伸长率,接头断后伸长率最高达16.5%.接头极化曲线测试表明,当送丝速度为7.5 m/min时,自腐蚀电流密度最小,腐蚀倾向最低. 相似文献
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研究了挤压-拉拔的纯镁丝材在人工模拟体液和0.9%NaCl溶液中的腐蚀行为。通过测量纯镁丝材在人工模拟体液中的平均腐蚀速率和腐蚀后溶液的pH值来研究其腐蚀规律。通过扫描电子显微镜观察纯镁丝材腐蚀后人表面形貌,发现纯镁丝材的腐蚀机理为点腐蚀。而且,纯挤压拉拔的纯镁丝材在0.9%NaCl溶液中的腐蚀行为表明,丝材的晶粒越细小丝材所表现出来的耐腐蚀性能越好。 相似文献
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电化学方法检测混凝土横梁中高强钢丝的腐蚀 总被引:5,自引:1,他引:5
通过测量镦头自腐蚀电位等参数,判断吊杆钢丝的腐蚀概率;以吊杆钢丝和CCMP-I检测探头分别作为研究电极,运用恒电量技术检测获得Rp值和Tafel常数,从而计算出腐蚀速率icorr.检测结果表明:压浆对增强钢丝的保护有成效;由于锈蚀原因不同,各短吊杆位置钢丝的锈蚀速率差异很大. 相似文献
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油膜下局部腐蚀的探讨 总被引:3,自引:0,他引:3
采用丝束电极测试每一丝电极的电位、腐蚀电流大小,直观地探测油膜局部区域的电化学参数分布,研究油膜下的腐蚀情况。结果表明,各涂油丝束电极间存在电化学差异,油膜下存在腐蚀微电池,油膜下的腐蚀是分区进行的,阴极区受到保护,阳极区金属发生腐蚀。 相似文献