| 摘要: |
| 为了考察不同投料顺序对镁合金表面层状双金属氢氧化物（LDHs）涂层性能的影响，并得到一种具有较好耐腐蚀能力的镁合金防腐蚀涂层，通过水热合成法采用不同投料顺序在镁合金表面原位沉积LDHs涂层。使用SEM、XRD、EIS、Tafel曲线和直接浸泡的方法，分别对LDHs涂层的表面形貌、结构和耐腐蚀性能进行评估。结果发现，采用不同的投料顺序得到了不同表面形貌、相似结构和不同耐腐蚀能力的LDHs涂层。所有LDHs涂层的自腐蚀电位、自腐蚀电流密度和阻抗模量相对于基底都分别发生了明显的正移、下降和增加，电位正移值约为0.7 V，自腐蚀电流密度降低值达到3~4个数量级，阻抗模量增加约4个数量级。以上结果表明通过控制投料顺序可以得到具有不同表面形貌的LDHs涂层。采用向硝酸铝中添加硝酸镁后调节溶液pH，再加入碳酸钠的投料顺序，得到LDHs涂层在NaCl溶液中的耐腐蚀能力最好。 |
| 关键词: 镁合金 层状双金属氢氧化物 Tafel曲线 电化学阻抗谱 |
| DOI：10.11933/j.issn.1007-9289.20180307001 |
| 分类号:TG174.45;TG178 |
| 基金项目:国家自然科学基金（51501157）；四川省科学技术厅应用基础研究（2018JY0483）；西华师范大学留学归校人员科研资助专项（17B005） |
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| Effects of Feeding Process on Characteristics of Layered Double Hydroxide Coating on Mg Alloy |
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XIE Zhi-hui
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Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637002, Sichuan
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| Abstract: |
| To study the effects of different feeding processes on the characteristics of layered double hydroxide (LDH), and to obtain a coating with good corrosion protection on Mg alloy, in-situ deposition of LDHs coating on Mg alloy through hydrothermal method with different feeding processes was carried out. The surface morphologies, structures, and corrosion resistance of LDHs coatings were characterized by SEM, XRD, EIS, Tafel curves, and direct immersion measurements. The results show that LDHs coatings with different surface morphologies, different corrosion protection capabilities, and similar structures are obtained using various feeding processes. Compared with Mg alloy substrate, the corrosion potentials, corrosion current densities, and impedance modulus of LDHs coatings respectively shift positively by 0.7 V, decrease obviously by three to four orders of magnitude, and increase evidently by around four orders of magnitude. The surface morphologies of LDHs coatings are tunable by controlling the feeding processes. The coating deposited with a feeding process by adding magnesium nitrate into aluminum nitrate followed by pH adjustment and an addition of sodium carbonate, exhibits the best corrosion resistance in a NaCl solution. |
| Key words: magnesium alloy layered double hydroxide Tafel curves electrochemical impedance spectroscopy (EIS) |
