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以6063铝合金为基体,在由氟硅酸盐和氟化铵组成的转化液中制得无铬转化膜。以168h盐雾试验后试样未腐蚀面积分数为指标,研究了转化液组成和工艺条件对氟硅酸盐转化膜耐蚀性的影响。优化后氟硅酸盐转化的工艺参数为:Na2SiF63～5g/L,NH4F5～7g/L,pH5.5～6.5,温度25～35°C,转化时间12～16min。经氟硅酸盐处理后,铝合金表面得到由F、Al、Na、O和Si组成的、致密的无铬转化膜,铝合金的自腐蚀电位显著正移,耐蚀性提高。
Based on 6063 aluminum alloy, chromium-free conversion coating was prepared in the conversion solution composed of fluorosilicate and ammonium fluoride. The 168 h salt spray test uncorroded area score as an indicator to study the composition of the conversion fluid and process conditions on the corrosion resistance of fluorosilicate conversion coating. The optimized technological parameters of fluorosilicate conversion are: Na2SiF63 ~ 5g / L, NH4F5 ~ 7g / L, pH5.5 ~ 6.5, temperature 25 ~ 35 ° C, conversion time 12 ~ 16min. After treated with fluorosilicate, the surface of the aluminum alloy is composed of dense, chrome-free conversion coating composed of F, Al, Na, O and Si. The corrosion potential of the aluminum alloy is significantly positive and the corrosion resistance is improved.