| Author Name | Affiliation | | Bilan Lin | School of Material Science and Engineering, Xiamen University of Technology, Xiamen 361024, China
Key Laboratory of Functional Materials and Applications of Fujian Province, Xiamen 361024, China | | Yuye Xu | College of Civil Engineering, Huaqiao University, Xiamen 361021, China | | Jintang Lu | School of Material Science and Engineering, South China University of Technology, Guangzhou 510640, China |
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| Abstract: |
| The phosphated zinc layer was post-sealed with molybdate to obtain the composite coating without pores. The composition of the formed coating was investigated. The corrosion behavior of the coated samples was studied. The coated samples were first scratched and subsequently corroded in a neutral salt spray (NSS) chamber for 2-72 h; the microstructure of the corrosion products was analyzed via SEM and EDS; and the self-healing performance was discussed. The coating obtained contains Zn3(PO4)2·4H2O, Mo2O3 and MoO42-. The electrochemical impedance first increases and then decreases with the immersion time. However, after immersion for 6 days, it remains at about 10 kΩ·cm2, much higher than the value for the single-treated samples without corrosion. Micro structural observations show that the corrosion products in scratch increase in size and finally cover the whole scratch completely. The initial corrosion products have high P, Mo and O contents but almost no Cl, while in later stages the first three components decrease and Cl increases. The corrosion products form a compact mass of needle-like crystals, effectively inhibiting zinc corrosion. The composite coating exhibits good self-healing. |
| Key words: self-healing corrosion phosphate coating post-seal scratched |
| DOI：10.11916/j.issn.1005-9113.15306 |
| Clc Number:TG174.4 |
| Fund: |
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| Descriptions in Chinese: |
| 钼酸盐封闭后处理磷化膜的自愈行为 林碧兰1,2, 徐玉野3，卢锦堂4 （1. 厦门理工学院 材料科学与工程学院, 厦门 361024; 2. 福建省功能材料及应用重点实验室, 厦门 361024; 3. 华侨大学 土木工程学院, 厦门 361021; 4. 华南理工大学 材料科学与工程学院, 广州 510640）
创新点说明：1） 通过磷化和钼酸盐封闭后处理形成连续完整的复合膜。 2） 采用划伤和NSS腐蚀的方法研究了膜层的自愈性。 3） 划痕表面的腐蚀产物为致密、细小针状，不同于常规镀锌层表面絮状、疏松的碱式氯化锌“白锈”。 4） 复合膜具有良好的耐蚀性能和自愈性能。
中文摘要：用钼酸盐封闭后处理磷化的镀锌层以消除磷化膜的孔隙。利用X射线光电子能谱(XPS)分析了膜层的化学组成；通过电化学阻抗谱(EIS)测量研究了覆层试样在5%NaCl溶液中的腐蚀行为；覆层试样先划伤再在中性盐雾 (NSS)箱中腐蚀2~72 h，利用SEM和EDS观察划痕处腐蚀产物的显微组织并探讨了复合膜的自愈行为。结果表明，所形成的复合膜含有Zn3(PO4)2.4H2O, Mo2O3 和MoO42–。覆层试样的阻抗值随腐蚀时间的延长先增大再减小，但经6天的腐蚀后阻抗值仍保持在10 kΩ.cm2，明显高于单一处理试样未腐蚀的情况。显微分析表明，划痕处的腐蚀产物不断增多、长大、最终完全覆盖整个划痕表面。初始阶段形成的腐蚀产物含有较高含量的P、Mo和O元素、但几乎不含有Cl元素；而在腐蚀后期阶段，前三种元素的含量减少、Cl元素含量增多。划痕表面的腐蚀产物为致密、细小的针状晶体，有效抑制锌的腐蚀。复合膜具有良好的自愈特性。 关键词：自愈性; 腐蚀; 磷化膜; 后处理; 划伤 |
