Fe、Si、Cu和In含量对铝合金牺牲阳极性能影响研究

发布时间：2018-02-28 23:04

本文关键词： Fe Si Cu 铝合金牺牲阳极电化学性能　出处：《大连海事大学》2017年博士论文　论文类型：学位论文

【摘要】：铝合金牺牲阳极广泛应用于各类船舶、采油平台等海洋基础设施的腐蚀防护。目前国内外在牺牲阳极研究工作中主要采用改变合金元素含量或冶炼工艺的方法,然而关于杂质元素含量对铝合金阳极电化学性能影响的研究工作鲜见报导。因此,研究Fe、Si和Cu对铝合金阳极在海水中电化学性能的影响规律具有现实意义。本文采用电化学、微观扫描电化学测试方法和扫描电镜、电子探针、电感耦合等离子体质谱等现代物理测试技术,考查了不同Fe、Si、Cu和In含量对Al-Zn-In-Mg-Ti合金阳极在海水中电化学性能的影响规律,得出以下结论。Al-5Zn-0.02In-1Mg-0.05Ti(wt.%)合金中添加 0.10 wt.%Fe 时,可使牺牲阳极在海水中的工作电位处于-1.052～-1.067 V之间,实际电容量为2665.97 A.h.kg-1,电流效率达到92.89%。阳极的开路电位足够负,电化学极化性能较好,呈现低钝化膜电阻和高双电层电容的特性。而当Fe含量超过0.10 wt.%后,阳极活性溶解阻力增大,电流效率降低。Al-5Zn-0.02In-1Mg-0.05Ti(wt.%)合金中添加 0.09 wt.%Si 时,可使牺牲阳极在海水中的工作电位处于-0.918～-0.935 V之间,实际电容量为2450.94 A.h·kg-1,电流效率为85.42%。阳极的平均晶粒尺寸为47 μm,等轴晶增多,组织均匀性得到改善,在阴极保护过程中溶解均匀。当Si含量超过0.09wt.%后,铝合金钝化膜电阻增大,电流效率降低。Al-5Zn-0.02In-1Mg-0.05Ti(wt.%)合金中添加 0.005 wt.%Cu 时,可使牺牲阳极在海水中的工作电位处于-1.057～-1.078 V之间,实际电容量为2674.73 A.h·kg-1,电流效率高达93.22%,具备较好的溶解表观形貌。当Cu含量超过0.005 wt.%后,大幅增加腐蚀产物粘度,使合金钝化膜的电阻升高,活性溶解阻力增大,电流效率降低。Al-5Zn-0.02In(wt.%)三元合金中添加 0.10 wt.%Fe、0.09 wt.%Si 和 0.005 wt.%Cu时,可使铝合金牺牲阳极在海水中的工作电位处于-1.086～-1.102V,实际电容量为2595.34 A.h·kg-1,电流效率达到90.43%,阳极表面溶解均匀,能够提供稳定的驱动电位和溶解电流。同时添加Fe、Si和Cu,可产生元素间的协同作用,并验证了此含量配比对Al-Zn-In牺牲阳极电化学性能的影响规律存在普遍性。Al-5Zn-In-0.09Si-0.1Fe-0.005Cu(wt.%)合金中添加 0.02 wt.%In 时,可使铝合金牺牲阳极在海水中的工作电位大小适中,促使被保护金属发生阴极极化,避免阴极区的析氢自腐蚀。当In含量低于0.02 wt.%时,阳极不能被充分活化易出现局部腐蚀。当In含量高于0.02 wt.%后,阳极易形成较多的偏析相诱发大量晶间腐蚀,引起晶粒剥离,降低铝合金阳极电流效率。
[Abstract]:Aluminum alloy sacrificial anode is widely used in the corrosion protection of marine infrastructure such as ships and oil recovery platforms. At present, the methods of changing the content of alloy elements or smelting process are mainly used in the research of sacrificial anodes at home and abroad. However, there are few reports on the effect of impurity element content on the electrochemical properties of aluminum alloy anodes. Therefore, it is of practical significance to study the effect of Fe Si and Cu on the electrochemical properties of aluminum alloy anodes in seawater. In this paper, the effects of different contents of Fe, Si, Cu and in on the electrochemical properties of Al-Zn-In-Mg-Ti alloy anode in seawater have been investigated by means of scanning electron microscopy, electron probe, inductively coupled plasma mass spectrometry and other modern physical testing techniques, such as microscanning electrochemical measurement method, electron microprobe, electron probe, inductively coupled plasma mass spectrometry and so on. The following conclusions can be drawn: when 0.10 wtt. is added to Al-5Zn-0.02In-1Mg-0.05Tiwt.) alloy, the working potential of sacrificial anode in seawater is between -1.052 and 1.067 V, the actual capacity is 2665.97 A.h.kg-1, the current efficiency is 92.899.The open circuit potential of anode is negative enough, and the electrochemical polarization is good. When Fe content is more than 0.10 wt.%, the active dissolution resistance of anode increases, and the current efficiency decreases. Al-5Zn-0.02In-1Mg-0.05TiWT.) alloy is added 0.09 wt.%Si to the alloy, which is characterized by low passivation film resistance and high double layer capacitance, and when Fe content exceeds 0.10 wt.%, the anodic active dissolution resistance increases and the current efficiency decreases. The working potential of sacrificial anode in seawater is -0.918 ~ 0.935 V, the actual capacity is 2450.94 A.h 路kg ~ (-1), the current efficiency is 85.42, the average grain size of anode is 47 渭 m, the equiaxed crystal increases, and the structure uniformity is improved. When Si content exceeds 0.09wt.%, the passivation film resistance increases and the current efficiency decreases. When 0.005 wt.%Cu is added to the alloy, the working potential of the sacrificial anode in seawater is -1.057- 1.078V. The actual capacity is 2674.73 A.h 路kg-1, the current efficiency is 93.2222, and the dissolution surface morphology is better. When Cu content exceeds 0.005 wt.%, the viscosity of corrosion products is increased significantly, the resistance of passivation film increases and the active dissolution resistance increases. When 0.10 wt.0.09 wt.%Si and 0.005 wt.%Cu were added to the alloy, the working potential of the sacrificial anode in seawater was -1.086 -1.102 V, the actual capacity was 2595.34 A.h 路kg-1, the current efficiency reached 90.433.The anode surface was dissolved uniformly. It can provide stable driving potential and dissolving current. The synergistic effect between elements can be obtained by adding Fesi Si and Cu. It is verified that the effect of this ratio on the electrochemical properties of Al-Zn-In sacrificial anode is universal when 0.02 wt.%In is added to the alloy, Al-5Zn-In-0.09Si-0.1Fe-0.005Cuwt.twt. The working potential of the aluminum alloy sacrificial anode in seawater is moderate, and the cathodic polarization of the protected metal is promoted to avoid self-corrosion of hydrogen evolution in the cathodic region. When in content is lower than 0.02 wt.%, When the content of in is higher than 0.02 wt.%, the anode is prone to form more segregation phase to induce a large number of intergranular corrosion, which leads to grain stripping and reduces the anodic current efficiency of aluminum alloy.
【学位授予单位】：大连海事大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U672.72;U668

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