辛延琛,王友彬,陈志文,冯济强,高峰,汤宏群.杂质镓对纯铝表面锆钛转化膜的组织及耐腐蚀性能的影响[J].表面技术,2024,53(4):46-57.
XIN Yanchen,WANG Youbin,CHEN Zhiwen,FENG Jiqiang,GAO Feng,TANG Hongqun.Effect of Impurity Ga on the Microstructure and Corrosion Resistance of Zirconium Titanium Conversion Coating on Pure Al[J].Surface Technology,2024,53(4):46-57 |
| 杂质镓对纯铝表面锆钛转化膜的组织及耐腐蚀性能的影响 |
| Effect of Impurity Ga on the Microstructure and Corrosion Resistance of Zirconium Titanium Conversion Coating on Pure Al |
| 投稿时间：2022-12-24 修订日期：2023-05-18 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.04.004 |
| 中文关键词: 杂质镓 锆钛转化膜 局部腐蚀 扫描电化学显微镜 微区电化学 |
| 英文关键词:impurity Ga zirconium titanium conversion coating localized corrosion scanning electrochemical microscope (SECM) localized electrochemistry |
| 基金项目:广西自然科学基金面上项目(2021GXNSFAA196046);国家自然科学基金(11975082) |
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| Author | Institution |
| XIN Yanchen | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
| WANG Youbin | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
| CHEN Zhiwen | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
| FENG Jiqiang | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
| GAO Feng | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
| TANG Hongqun | School of Resources, Environment and Materials,State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China |
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| 中文摘要: |
| 目的 探究杂质镓对纯铝锆钛转化膜的生长规律和防护性能的影响。方法 采用扫描电化学显微镜(SECM)技术表征了含镓纯铝表面锆钛转化膜在3.5%(质量分数)NaCl溶液中局部腐蚀的演变过程，结合X射线衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)等技术分析了镓对纯铝锆钛转化膜的组织及成分的影响规律，采用开路电位法(OCP)、电化学阻抗技术(EIS)以及极化曲线(Tafel)等探究了杂质镓对纯铝表面转化膜的生长和耐腐蚀性能的影响规律。结果 锆钛转化膜主要由冰晶石Na3AlF6、氧化物(如TiO2、ZrO2、Al2O3)和有机金属络合物组成;杂质镓的添加会抑制铝表面转化膜的生长，破坏膜层的完整性。随镓含量(质量分数)从0%增大到0.5%，锆钛转化膜阻抗值从4.75×104 Ω.cm2不断减小到2.49×103 Ω.cm2，自腐蚀电流密度由0.45 μA增加到13.4 μA，腐蚀电位从−0.485 V降低到−0.890 V，耐腐蚀性能逐渐降低。在锆钛转换膜的SECM微区腐蚀演变过程中，膜层自修复行为会降低膜层的被腐蚀倾向，但富集在表面的镓会抑制自修复膜层的形成，导致基体被严重腐蚀。结论 铝中的杂质镓能够直接影响锆钛膜的完整性，降低对铝基体的保护，导致了铝基体局部腐蚀溶解的发生。 |
| 英文摘要: |
| Al alloys are widely used in many applications such as aerospace, rail transit, automobile, and power electronics industry due to the advantage of low density, high strength, and good formability. However, Al alloys are easily corroded in the solution containing Cl− ions, which causes local corrosion, such as pitting corrosion and intergranular corrosion, resulting in the decrease of service life. To improve the corrosion resistance of Al alloys, zirconium titanium (Zr/Ti) conversion coating is usually prepared to protect the Al substrate. Ga is the one of the main impurity elements in Al alloy, and can enhance the electrochemical activity of Al alloy in the corrosive medium, which makes it challenging to generate natural dense oxide film on the surface of Al alloys and significantly reduces the corrosion resistance of the Al alloy. During the preparation process of Zr/Ti conversion coating, Ga dissolved from the Al substrate can be enriched on the surface, which is a hidden danger to the protective performance of the Zr/Ti conversion coating. At present, there is little research on the adverse effect of Ga on the Zr/Ti conversion coating, which needs further exploration. The work aims to explore the effect of impurity Ga on the growth and protective properties of the Zr/Ti conversion coating. The evolution of local corrosion of Zi/Ti conversion coating on pure Al containing gallium in 3.5wt.% NaCl solution was characterized by scanning electrochemical microscope (SECM). The effect of impurity Ga on composition of coating was investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning electron microscopy (EDS). The growth of the Zr/Ti conversion coating on Pure Al was studied by open circuit potential (OCP), and the electrochemical impedance spectroscopy (EIS) and polarization curve (Tafel) were used to investigate the variation of corrosion resistance of conversion coating on pure Al with Ga content. The Zi/Ti conversion coating was mainly composed of Na3AlF6 and organic metal complexes, in addition to oxides such as TiO2, ZrO2, and Al2O3. The impurity Ga could inhibit the growth of the Zr/Ti coating, and reduce the integrity of the Zr/Ti coating. The corrosion resistance of the Zr/Ti conversion coating significantly decreased with the increase of Ga content from 0% to 0.5%, the electrochemical impedance of the Zr/Ti conversion coating decreased from 4.75×104 kΩ to 2.49×103 kΩ, the corrosion current density of coating increased from 0.45 μA to 13.4 μA, and the corrosion potential decreased from −0.485 V to −0.890 V. During the evolution of SECM micro-zone corrosion of the Zr/Ti conversion coatings, the self-healing behavior of the coatings could reduce the corrosion tendency. However, Ga enriched on the resurface could inhibit the formation of self-repairing film, leading to severe corrosion of the Al substrate. Therefore, the impurity Ga in Al can directly affect the integrity of the Zr/Ti coating, and reduce the protection of the Al substrate, leading to the occurrence of localized corrosion and dissolution of the Al substrate. |
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