镁合金表面不同MOF超疏水涂层的耐蚀行为

Corrosion resistance behavior of different MOF superhydrophobic coatings on magnesium alloy surface

对AZ91D镁合金表面三种不同超疏水涂层(MZS-1,MZS-2和ZnO@ZIF-8)在5%(质量分数)NaCl溶液中的耐蚀性能进行研究。采用场发射扫描电子显微镜、静态接触角测试仪、电化学工作站和盐水喷雾试验机分别对超疏水复合涂层进行微观形貌、润湿性、耐蚀性能等进行测试与表征。结果表明:经过盐雾处理后,三种超疏水涂层均在192 h后出现腐蚀,其中MZS-1超疏水涂层的腐蚀最为严重,MZS-2超疏水涂层240 h后表面出现点蚀,同时经过盐雾处理后仍能维持较高的接触角,故MZS-2复合涂层耐蚀性能最好。极化曲线测试发现,在盐雾处理240 h后,三种超疏水涂层的腐蚀电流密度仍比金属基体降低1个数量级,表现出优异的耐蚀性能。所制备的超疏水涂层可以有效增加金属材料的耐蚀性,由于超疏水涂层的拒水性,有效阻挡腐蚀离子的渗透,给基体提供长期的防护作用。

In order to study the corrosion resistance of three different superhydrophobic coatings(MZS-1,MZS-2 and ZnO@ZIF-8)on AZ91D magnesium alloy surface in 5%(mass fraction)NaCl solution.The microstructure,wettability and corrosion resistance of the superhydrophobic composite coating were tested and characterized by field emission scanning electron microscope,static contact angle tester,electrochemical workstation and salt spray tester,respectively.The results show that the corrosion of the superhydrophobic coatings does not occur until 192 h after salt spray treatment among the three types of superhydrophobic coatings,and the corrosion of the MZS-1 superhydrophobic coating is the most serious.The surface pitting of the MZS-2 superhydrophobic coating doesn’t occur until 240 h later,and the contact angle is still high after salt spray treatment,so the corrosion resistance of the MZS-2 composite coating is the best.The polarization curve tests indicate that the corrosion current density of three superhydrophobic coatings are still one order of magnitude lower than that of the metal matrix after salt spray treatment for 240 h,showing excellent corrosion resistance.The superhydrophobic coating can effectively increase the corrosion resistance of metal materials.It can effectively prevent the infiltration of corrosive ions and provide longterm protection for the matrix because of its water repellency.