共查询到19条相似文献,搜索用时 109 毫秒
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不同腐蚀环境对7475-T7351铝合金疲劳性能及裂纹扩展速率的影响 总被引:3,自引:0,他引:3
采用轴向加载疲劳和疲劳裂纹扩展速率性能测试方法,研究了不同腐蚀环境对7475-T7351铝合金厚板疲劳及裂纹扩展性能的影响.结果表明:腐蚀环境对7475铝合金的疲劳性能有较大影响,油箱积水和3.5%(质量分数,下同)NaCl溶液中光滑试样的疲劳强度较室温下降约68%,油箱积水和3.5%NaCl溶液环境对材料疲劳强度的影响程度基本相同;不同环境腐蚀(空气和3.5%NaCl)和不同温度(室温和125℃)对材料的低周疲劳性能影响不大;腐蚀环境对裂纹扩展有较明显的加速作用,油箱积水和3.5%NaCl溶液环境对裂纹扩展的加速规律基本一致. 相似文献
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高强铝合金加速腐蚀方法的研究 总被引:2,自引:0,他引:2
以pH=3.0的5%NaCl+0.5%(NH4)2SO4溶液为加速剂,对LY12和LC4两种高强铝合金进行了间歇盐雾和周期轮浸腐蚀试验。结果表明,两种加速腐蚀方法之间有类似的腐蚀动力学规律,其中前者相对于大气腐蚀有较好的模拟性和加速性。根据材料腐蚀动力学规律提出了“参照腐蚀率”的概念,并以此作为腐蚀程度的评估准则,定量评定了间歇盐雾相对于大气腐蚀的加速性。 相似文献
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在舰船的舱底积水和海水管系中,微生物腐蚀是重要的腐蚀形式之一。在众多的微生物中以硫酸盐还原菌(SRB)的腐蚀最为严重,主要表现为微生物的生长代谢在金属表面形成生物膜,改变了生物膜内的微环境,其代谢产物与金属基体相互作用,加速了金属的腐蚀过程.文中从微生物的生理学、腐蚀机理等角度,对舰船材料的腐蚀危害、微生物腐蚀研究方法和腐蚀防治措施以覆微生物腐蚀的近期研究状况等几个方面进行了综述,并展望了微生物腐蚀研究的发展趋势. 相似文献
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使用PLINT微动腐蚀试验机,位移幅值(D)为100~250μm,法向载荷(Fn)为20~80N,频率(f)为2 Hz,循环次数(N)为10 000次,在3.5%的NaCl溶液中进行了Inconel 690合金微动腐蚀试验。结果表明:微动腐蚀与磨损成正交互作用,腐蚀对磨损的促进量是交互作用量增加的主要部分;微动引起腐蚀电位负移,载荷和位移幅值增加均引起腐蚀电流及腐蚀速率增加;磨痕表面可观察到磨损与腐蚀共同作用及相互促进的形貌特征。Inconel 690合金在3.5%的NaCl溶液中的微动腐蚀机理主要是磨损腐蚀、剥层和磨粒磨损的递进及协同作用。 相似文献
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铜在甲胺-铁氰化钾化学机械抛光液中的腐蚀与钝化 总被引:2,自引:1,他引:1
用电化学测试技术研究了腐蚀介质和成膜剂浓度对铜表面的腐蚀与钝化成膜的影响,分析了钝化膜的成分,探讨了钝化膜在抛光压力和转速作用下的磨损与表面再钝化的行为,测量了铜在化学机械抛光过程中的极化曲线。结果表明铜在甲胺溶液介质铁氰化钾抛光液中易钝化,钝化膜的主要成分为Cu4[Fe(CN)6],有少量Cu20存在。钝化膜的磨损特性随成分浓度不同而不同。钝化膜的磨损难易程度与钝化膜的本身特性、抛光压力及转速有关。抛光过程中因钝化膜被磨损,腐蚀加快,腐蚀电流密度大幅增加。配方0.1%甲胺溶液 0.5%K3Fe(CN)6 5%Al2O3可行。 相似文献
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使用大气气候变化数据,改进了氯离子作用下腐蚀开始时间模型和腐蚀电流密度模型,分析了全球变暖(CO2浓度和温度)对RC桥梁在氯离子腐蚀作用下的锈胀开裂性能影响。考虑腐蚀影响的性能预测参数如气候变化、氯离子浓度、氯离子扩散过程、温度、湿度、结构尺寸参数、钢筋位置和性能退化机制等具有随机性和时变性,发展了基于时变可靠度理论的预测方法来预测RC桥梁在将来全球变暖作用下以及氯盐环境下将来服役100年内的开始腐蚀风险和平均锈胀开裂概率。研究发现:1) 在预测氯离子腐蚀效应时,大气气候变化温室效应能够恶化混凝土腐蚀损伤效应,在预测时需要计入其效应;2) 在浪溅区环境下的开始腐蚀概率和锈胀开裂比例比海岸线大气区环境下分别高了127%和140%,当结构位于距离海岸线1km以上区域时锈胀开裂比例降低到1%;3) 对于保护层厚度为20mm和水灰比为0.55的混凝土,在将来100年内的开裂概率为0.893,这意味着大多数混凝土结构在服役期存在腐蚀损伤现象,将来需要大量的维修和维护工作。这些信息能够为决策人员应对温室效应和氯离子腐蚀对土木工程的影响做出应对措施提供支持。 相似文献
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Effects of oxygen active elements, yttrium and cerium, as additives in commercial lubricants on corrosive wear were investigated. Sliding wear losses of stainless steel 304 and Al alloy 6061 lubricated by oil and thin grease respectively with and without yttrium or cerium additive in a corrosive environment were determined. Dilute H2SO4 solution (10% H2SO4) was used as the corrosive medium and added to the lubricants for the corrosive wear test. The wear test was performed on a pin-on-disc tribometer with the capability of measuring wear in lubricant. The disc was coiled with a copper tube, through which cooling water could pass, so that the wear losses respectively under cooling condition and non-cooling condition could be determined. The results showed that wear losses of the tested materials caused by synergistic attack of wear and corrosion can be effectively reduced by adding small amounts of yttrium or cerium to the lubricant. In addition, the effect of the additives was found more distinctive under the non-cooling condition. Worn surfaces were examined using SEM to clarify the wear mode and thus the wear mechanism. 相似文献
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The present work examines how passivating oxide film affects the corrosive wear rate of Al-7%Si alloy in H2SO4 solution at room temperature. As the applied potential (relative to a saturated calomel electrode (SCE)) increases to 1.08 VSCE on an Al-7%Si alloy specimen, the corrosive wear rate increases and then decreases for polarization to higher anodic potentials. The corrosive wear rate Wcw consists of three factors, namely pure mechanical wear loss Wmech, weight loss Wdiss caused by the corrosion reaction, and an acceleratory-deceleratory contribution Wacc due to the presence of passivating oxide film. The acceleratory and deceleratory contributions Wacc arising from compositional change of the passivating oxide film indicate the microcutting and microploughing mechanisms respectively of abrasive wear. The increased Wacc by application of 1.08 VSCE is discussed from the viewpoints of hydration and severe abrading wear action of the passivating oxide film on the Al-7%Si alloy specimen. 相似文献
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不锈钢具有良好的耐蚀性、韧性和可加工性,但其硬度低、耐磨性差,严重制约了其在有磨损腐蚀要求环境体系中的应用.为了提高不锈钢的抗磨损性能,通过低温活性盐浴表面处理技术提高其耐磨性的同时不降低其耐蚀性,使得其在具有磨损的腐蚀介质环境中能够提高其抗磨损性能而不被腐蚀,可延长其使用寿命.本文系统地介绍了低温活性盐浴表面氮化处理技术的发展、原理及应用和处理后表面氮化层的特点、组织和表面性能.低温活性盐浴表面处理后,表层活性N原子扩散在奥氏体间隙中形成过饱和固溶体的S-相,产生特殊的位错-应力FCC结构,使得奥氏体晶格发生严重变形,不但提高了其腐蚀性,同时大大提高了其硬度,使得不锈钢硬度能够达到1 000 HV0.1,其抗磨损性能亦得到了显著提高. 相似文献
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A global model is proposed in this study to predict prestressed concrete (PC) cracking induced by strand corrosion. The proposed model considers the three stages: micro-crack formations, cover cracking initiation, and crack width growth. The prestress and geometric properties of the strand have been incorporated into the prediction. Six PC beams were designed and accelerated toward corrosion-induced cracking. Observing the strands supported visual evidence of pitting corrosion and crevice corrosion. The effects of corrosion-induced crack on the failure of beams are analyzed. The proposed model is verified by the experimental results and this work presents the effects of parameters on corrosion-induced cracking. The results show that prestress has an adverse effect on corrosion-induced cracking. Prestress leads to a decrease in the critical corrosion loss at the three stages. This decrement becomes more noticeable with increasing cover and decreasing concrete tensile strength, but shows no remarkable changes with an increasing strand diameter and rust expansion ratio. 相似文献
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阴极极化对滑移区微动腐蚀行为的影响 总被引:1,自引:0,他引:1
研究了45^#、GCr15和0Cr18Ni9钢在水、酸雨和海水介质中的微动腐蚀特性,以及阴极极化作用的影响.结果表明:与干态和水介质的情况相比,在酸雨和海水中这3种钢的摩擦因数降低,阴极极化使摩擦因数升高.在酸雨和海水介质中3种钢的微动腐蚀材料流失量均小于干态,阴极极化显著降低了微动腐蚀损伤和材料流失.在微动腐蚀条件下材料的流失小于干态,微动与腐蚀之间表现出“负”交互作用,是介质及其产生的腐蚀产物膜参与微动过程的原因,从而改变了摩擦副接触区表面状态,减少了摩擦副直接接触. 相似文献