多壁碳纳米管含量对无铬锌铝涂层耐蚀性能的影响

Effect of MWCNTs Content on Corrosion Resistance of Chromium-free Zinc-aluminum Coatings

针对无铬锌铝涂层耐蚀性不足的问题,通过超声波分散的方法制备了不同多壁碳纳米管(MWCNTs)含量的无铬锌铝涂层,研究了MWCNTs含量对无铬锌铝涂层宏观及微观形貌、成分、结合力及耐蚀性能的影响。结果表明:添加MWCNTs质量分数为0%~0.7%时,所有涂层外观均完整平滑,连续致密。MWCNTs含量为0.3%时,在涂层中分散良好,涂层结合力最佳,耐NaCl溶液腐蚀性能最好,且可以为基体提供良好的阴极保护作用,其自腐蚀电流密度仅为2.019×10^(-5)A/cm^(2),阻抗模量较未加MWCNTs的涂层大一个数量级。此外,对MWCNTs影响涂层耐蚀性的机理也进行了分析。

Novel chromium-free zinc-aluminum coatings with different content of multi-walled carbon nanotubes (MWCNTs) were prepared by ultrasonic dispersion method.The effect of MWCNTs on the morphology,composition,adhesion and corrosion resistance of chromium-free zinc aluminum coatings were investigated by means of scanning electron microscope (SEM) and energy dispersive spectrometer(EDS) and adhesion tester as well as immersion test in 3.5%Na Cl solution with electrochemical impedance spectroscopy and polarization curve measurement.Results show that when the MWCNTs content was 0%~0.7%,the coatings were smooth flat and dense,the flaky zinc powders and aluminum powders were parallel to the substrate,providing a good physical shielding.When the MWCNTs content was0.3%,the coating had the best adhesion and showed the best corrosion resistance in Na Cl solution,its free-corrosion current was 2.019×10^(-5)A/cm^(2),and impedance modulus reached 10^(3)Ω·cm^(2).In addition,the mechanism of MWCNTs affecting the corrosion resistance of the coating was explored.