采用Ce(NO3)3为主盐的稀土盐处理溶液，在AZ91镁合金表面形成无毒，无污染的铈盐化学转化膜，并研究成膜规律及其耐蚀行为。利用对膜层的外加扰动小，更易得到重复性高结果的电化学阻抗谱技术评价膜层耐蚀性能。初步优化了处理时间、温度、Ce(NO3)3液浓度和促进剂等因素对膜层结构和膜层耐蚀性能的影响，并获得了最好的成膜条件：温度35℃，时间为30min，处理液主盐Ce(NO3)3的浓度为0.02mol/l和4ml/l成膜促进剂。结果表明：优化后的工艺能够在AZ91镁合金表面获得宏观黄色致密，微观具有微小裂纹并分层的膜层，内层膜Ce含量较外层的低但致密。工艺优化制备的稀土化学转化膜能有效提高镁合金的耐蚀性能，有效抑制阴阳极反应，自腐蚀电位提高240mV，自腐蚀电流密度降低达到2个数量级。
In order to development an environmental friendly surface coating technology for magnesium, a chrome-free Ce-based process to form a conversion coating on AZ91 magnesium alloy was investigated. Electrochemical impedance spectroscopy (EIS) was chosen to evaluate corrosion resistance due to its low effect on electrochemical test system for getting high reproduction result. The effect of treatment time, temperature of electrolyte, concentration of Ce(NO3)3 and accelerant concentration on corrosion resistance was summarized, while a optimized technology was achieved, 0.02mol/l Ce(NO3)3, 4ml/l accelerant at 35℃ for 35 min. The results indicated that the chemical conversion formed in optimized technology presented yellow and impact surface by naked eye, while took on two layer structure with micro cracks on the outer layer. The content of Ce in inner layer was low than that of outer layer, while it was more impact. Tafel plots indicated that conversion film restrained the anodic and cathodic reaction on the interface, while the corrosion potential shifted anodic 240mV and corrosion current density decreased about 100 times.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] | |
| [12] | |
| [13] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%