桐油覆膜Ni-Co-SiO2纳米复合涂层的制备及防腐性能研究

Preparation and corrosion resistance of tung oil coated Ni-Co-SiO2 nanocomposite coatings

采用恒电位法在瓦特型电镀液中于碳钢表面制备了Ni-Co-SiO2纳米复合涂层,通过浸渍桐油处理制备桐油覆膜Ni-Co-SiO2涂层。利用场发射扫描电镜、能谱仪、X射线衍射、红外光谱仪、三维视频显微镜等表征涂层的形貌、元素组成、结构和粗糙度。采用Tafel动态极化曲线和电化学阻抗测试比较覆膜涂层和未处理涂层的耐蚀性。通过浸泡试验,对桐油覆膜涂层进行防腐蚀性评价。结果表明:桐油处理后涂层明显被一层薄膜涂覆,其表面粗糙度降低,但涂层前后的微观结构不变。桐油覆膜Ni-Co-SiO2涂层具有较低的腐蚀电流密度,较大的容抗弧和较高的阻抗模量。此外,长期浸泡试验表明,涂层低频阻抗模值在很长一段时间保持高于10~6Ω/cm~2,表明桐油覆膜Ni-Co-SiO2具有较高的耐腐蚀性。

Ni-Co-SiO2nanocomposite coatings were prepared on the surface of carbon steel in Wat electroplating solution by potentiostatic method,and the modified Ni-Co-SiO2coating was prepared by impregnation treatment in tung oil.The morphology,element,structure and roughness of the coatings were characterized by field emission scanning electron microscopy,energy dispersive spectroscopy,X-ray diffraction,infrared spectroscopy and three-dimensional video microscopy.The corrosion resistance of coated and untreated coatings was characterized by Tafel potentiondynamic polarization and electro‐chemical impedance tests.The corrosion resistance of tung oil coated coating was evaluated by immer‐sion test.The results showed that after tung oil treatment,the coating was obviously coated with a layer of thin film,and its surface roughness was reduced,but the microstructure before and after coating re‐mained unchanged.The modified Ni-Co-SiO2coating has lower corrosion current density,larger capaci‐tive arc and capacitive arc impedance modulus.In addition,the long-term immersion test showed tha the low-frequency impedance modulus of the coating remained higher than 10~6Ω/cm~2 for a long period of time,indicating that the modified Ni-Co-SiO2coating has high corrosion resistance.