6061铝合金表面硅烷-镧盐杂化膜制备工艺参数的正交优化

为探索硅烷-稀土盐复合膜的最佳制备工艺,以La(NO_3)_3·6H_2O为成膜物质,H_2O_2为促进剂,在铝合金表面制备硅烷-镧盐杂化膜,以膜层的极化电阻作为评价指标,采用正交试验法对制备工艺进行优选,采用电化学极化曲线和交流阻抗谱分析膜层的耐腐蚀性能,采用扫描电镜观察膜层的形貌,并与单一硅烷膜和镧盐膜的性能进行比较。结果表明:杂化膜的最佳制备工艺中镧盐沉积条件为10 g/L La(NO_3)_3·6H_2O,15 mL/L H_2O_2,成膜温度50℃,成膜时间40 min;镧盐掺杂有效提高了膜层的均匀度与致密度;杂化膜较单一硅烷膜和镧盐膜具有更好的致密性和疏水性,且能明显发挥镧盐膜和硅烷膜的协同作用,可有效降低6061铝合金的腐蚀速率,提高其耐蚀性。

Orthogonal Optimum of Technological Parameters for Preparation of Silane-Lanthanum Salt Hybrid Film on 6061 Aluminum Alloy

The orthogonal experiment was adopted to optimize the technological parameters of silane-lanthanum salt hybrid film on 6061 alumi num alloy with La(NO3) 3 · 6H2O and H2O2 as additive accelerant according to the polarization resistance as evaluation index.By electrochemical impedance spectroscopy and polarization curves,the corrosion resistance of the hybrid film,blank sample,silane film and lanthanum salt conversion film was analyzed.The surface morphology of the films was observed by scanning electron microscope.Results showed that the opti mal technological parameters were as follows:10 g La(NO3)3 · 6H2 O,15 mL/L H2O2,processing temperature of 50 ℃,and processing time of 40 min.The doping of lanthanum salt improved the uniformity and density,and the hybrid film had better density and hydrophobic property.The silane film and lanthanum salt conversion film had obvious synergistic effect,which effectively reduced the corrosion rate of 6061 aluminum alloy and improved the corrosion resistance.