论文总字数：17302字

摘 要

Mg合金是当今广泛使用的最轻的结构材料。在室温下，Mg合金具有密度低，无磁性，铸造性能低，腐蚀电位低的优点。因此，Mg合金越来越多地用于数字产品和海水阳极材料。由于Mg的熔点低，表面容易腐蚀和氧化，因此进一步研究Mg-Ga合金的腐蚀行为对Mg合金阳极材料的合金设计和组织演变具有重要意义。 本实验主要采用恒电位氧化试验，Tafel极化曲线法研究Mg-Ga合金的放电行为和自腐蚀行为。

（1）Mg-Ga固溶体的电化学活性随着Ga含量的提高而提高，在存在大量第二相的Ga含量为4at.%的Mg-Ga合金中，腐蚀电流密度是平常固溶体的4倍。在极化过程中，点蚀、局部腐蚀、全面腐蚀都有发生。但当Ga含量低于3 at.%时，Mg-Ga二元合金的腐蚀类型主要是点蚀。

（2）时效120 h后的Ga4 at.%的Mg-Ga合金电化学性能较好，此时Mg基体成分均匀，存在部分弥散分布的第二相，电位较负，Mg-Ga阳极自腐蚀较慢，电流效率较。热处理工艺可以使Mg阳极中的合金元素分布均匀，减少因成分、组织的不均匀而引起的微观电偶腐蚀的形成，从而提高了Mg阳极自身的耐蚀性。

关键词：Mg-Ga阳极 塔菲尔曲线 腐蚀

Study on Electrochemical Oxidation Behavior of Mg-Ga Alloy

Abstract

Magnesium alloys are the lightest structural materials that are widely used today. At room temperature, magnesium alloys have the advantages of low density, non-magnetic properties, low casting properties, and low corrosion potential. Therefore, magnesium alloys are increasingly used in digital products and anode materials for seawater. Because the melting point of magnesium is low, the surface is susceptible to corrosion and oxidation, and further study of the corrosion behavior of Mg-Ga alloys is of significance for the alloy design and microstructure evolution of magnesium alloy anode materials. This experiment mainly uses the constant potential oxidation test, Tafel polarization curve method to study the Mg-Ga alloy discharge behavior and self-corrosion behavior.

(1) The electrochemical activity of magnesium-germanium solid solution increases with the increase of niobium content. In magnesium niobium alloys with a large amount of second phase niobium content of 4at.%, the corrosion current density is 4 times that of normal solid solution. During the polarization process, pitting, localized corrosion, and total corrosion occur. However, when the niobium content is less than 3 at.%, the corrosion type of the magnesium niobium binary alloy is mainly pitting.

(2) The electrochemical properties of Ga 4 at.% magnesium niobium alloy after aging for 120 h are good. In this case, the magnesium matrix has uniform composition, there is a partially dispersed second phase, the potential is relatively negative, and the magnesium niobium anode has slow self-corrosion, and the current efficiency is Relatively. The heat treatment process can evenly distribute the alloying elements in the magnesium anode, reduce the formation of microscopic galvanic corrosion caused by the non-uniform composition and organization, thereby improving the corrosion resistance of the magnesium anode itself.

Keywords: Magnesium germanium anode; Tafel curve; corrosion

目 录

摘要 Ⅰ

Abstract Ⅱ

第一章 绪论 1

1.1Mg合金的概述 1

1.2合金元素在Mg阳极中的作用 2

1.3海水用Mg阳极材料 2

1.4 研究目的 3

第二章 实验方法 4

2.1实验仪器 4

2.2 实验流程图 5

2.3合金样品制备 5

2.4 组织观察 6

2.5 电化学实验 7

第三章 Mg-Ga合金电化学行为研究 8

3.1 电化学原理 8

3.2 金相观察 9

3.3恒电势氧化测试 16

3.4 Tafel极化曲线 17

3.5 失重法测腐蚀速率 15

第四章 结论 19

参考文献 24

致谢 27

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