Electrochemical characteristics of Al-Mg and Al-Mg-Si alloy in sea water

Among Al alloys,particularly 5000 series Al Mg and 6000 series Al Mg Si often used as marine materials have excellent corrosion resistance,low melting point,and thereby showing recycling availability when compared to other metals.Variety experiments were conducted to select the most suitable material for marine environments.All electrochemical experiments were conducted in natural seawater.The corrosion test was performed in many methods such as anodic/cathodic polarization and Tafel analysis using multi-channel potentio/galvanostat WMPG 1000.As results,anodic and cathodic polarization behaviors indicate the characteristics of passive state and concentration polarization by reduction reaction in dissolved oxygen,which shows excellent electrochemical behaviors.Tafel analysis results show no significant difference but 5052-O alloy of various alloy materials indicates the lowest corrosion current density.Therefore,5052-O Al alloy presents most anti-corrosion material in marine environment.

F-Si封闭剂对热喷涂15%Al-85%Zn合金涂层电化学行为的影响(英文)

大部分船体外壳通过喷漆、牺牲阳极和外加电流阴极保护方法来解决抗腐蚀问题。但是,这些传统的方法不是非常有效,因为船尾的船舵常暴露在严重的腐蚀环境中,例如潮汐、船行驶速度、气蚀和冲刷腐蚀。由于气泡的生成与破裂而产生的振荡波而导致的气蚀和冲刷腐蚀会对材料产生破坏。对热喷涂Al-Zn合金涂层进行了气蚀和电化学性能测试实验。然后,Al-Zn合金涂层表面涂刷F-Si封闭剂以提高Al-Zn涂层的耐海水电化学腐蚀和抗气蚀性能。结果表明,该封闭剂不但适用静态环境,而且适用于动态环境。

采用密封材料的热喷涂层的空蚀和电化学特征(英文)

抗腐蚀热喷涂技术广泛地运用于防止钢在海洋环境中由于腐蚀和气蚀受到损害。为了改善用于船舶材料的低温热喷涂85%Al-14.5%Zn-0.5%Zr涂层合金的耐久性,对其采用了多种密封材料,并考察其电化学行为和空蚀特征。结果表明:密封材料能改善涂层材料的性能。其中,混合陶瓷和氟-硅密封材料有着良好的电化学性能,并且氟-硅密封材料具有最佳的抗空蚀性能。

Electrochemical characteristics of HVOF spray coated layer with WC-27NiCr and WC-10Co4Cr for Al bronze

Among the environmentally friendly marine energies,tidal current power plants require low cost because they do not need to construct a large dam.Tidal power is particularly reliable energy source because the power generation capacity is predictable regardless of weather or season.Composite materials or stainless steel have been used as materials of blades for current power plant.However,their strength and welding performance generated many problems in field application.Copper alloys with excellent cavitation resistance and corrosion resistance were applied as blade materials to improve the durability of copper alloys.They were coated with WC-27NiCr and WC-10Co4Cr using the high velocity oxy-fuel (HVOF) method.The metal spray coating technology has the advantage in terms of the selection of materials for cost effectiveness and environmental effects of corrosion because the properties of the coat layer can be controlled intentionally.Coating with WC-27NiCr and WC-10Co4Cr by HVOF,WC-27NiCr shows better corrosion resistance overall.The reason for this seems to be that corrosion resistance improves and a stable passive film forms due to the effects of Ni and Cr.

Optimum condition by mechanical characteristic evaluation in friction stir welding for 5083-O Al alloy

The mechanical characteristies for friction stir welding (FSW) of 5083-O Al alloy were evaluated. The results show that in FSW at 800 r/min and 124 mm/min, a weld defect is observed at the start point. However, the button shape at the end point is good and the stir zone has a soft appearance. At 267 mm/min, a void occurs at the button. A slight weld defect and rough stir zone are seen both at the start and end points at 342 mm/min. Moreover, at the bottom, a tunnel-type void is observed from an early stage to the end point, and at 1 800 r/min, a weld defect can be found from an early stage to the end point. These defects are rough with imperfect joining due to excessive rotation speed and high physical force. Weld fractures relative to rotational and travel speeds are observed at the stir zone. The optimum FSW conditions are a welding speed of 124 mm/min and a rotational speed of 800 r/min.

流速对船舶海底阀箱5083-H116铝合金电化学行为的影响(英文)

研究流速对铝制船舶的海底阀箱材料5083-H116铝合金电化学行为的影响。为检测电化学特性和流速对其性能的影响,实验在静态和通过搅拌仪产生的4个不同流速下进行,并使用超声波振荡器利用压电效应进行空化实验。结果表明,合金在施加流速后其腐蚀电流密度和损害程度较在静态环境下增加,更易于发生腐蚀。

5083-H116铝合金在气蚀条件下的恒电位腐蚀防护技术(英文)

研究铝合金5083-H116在海水中的气蚀损伤行为特征,以期提高合金的耐气蚀性能。通过在不同电位条件下进行的恒电位实验,确定抑制气蚀损伤的最优保护电位。实验在电位为-2.2^-1.4 V的范围内进行,这对应于铝合金5083-H116阴极极化曲线上的浓差极化和活化极化区域。对实验获得的电流密度—时间曲线进行研究,通过三维显微镜和扫描电子显微镜分析合金表面的损伤情况。结果表明,合金的最优保护电位为-1.9^-1.5 V,在此电位条件下,合金的气蚀损伤得到显著地减轻。

Conjunctival cystectomy assisted by pattern scan laser photocoagulation

Background: To introduce a new technique of laser-assisted conjunctival cystectomy using pattern scan laser(PASCAL) photocoagulation.Case presentation: A 50-years-old Asian woman presented with a conjunctival cyst in the left eye. Slit-lamp examination revealed a 5 mm×2 mm sized freely movable conjunctival cyst. After a 1 mm×1 mm sized conjunctival opening was made using PASCAL photocoagulation, the cyst was extracted using a non-toothed forceps without rupture. Two weeks later, complete re-epithelialization of the conjunctiva was observed without any complications. No evidence of recurrence was noted over the 6-month follow-up period.Conclusion: Conjunctival cystectomy with the adjunctive use of PASCAL photocoagulation can be an effective and safe treatment method.