6061铝合金氟钛酸盐转化膜耐蚀性能的改性研究

Modification Research of Fluorinetitanate Conversion Coating Resistance on 6061 Aluminum Alloy

摘要: 采用单因素试验研究了氟硅酸铵、络合剂及缓蚀剂对 6061 铝合金表面氟钛酸盐转化膜耐蚀性能的影响。结果表明, 最佳的转化液成分及转化条件为: 氟化钠3 g/L, 氟硅, 酸铵4 g/L, 六偏磷酸钠1.0 g/L, 钛盐1.5 g/L, H2O2 1.5 ml/L, 常温下转化处理10 min, 处理液pH 5.0。采用SEM, EDS和极化曲线方法测试了改性后转化膜的形貌及耐蚀性。结果表明, 改性后的氟钛酸盐转化膜由连续而致密的晶体颗粒组成; 氟钛酸盐转化膜使 6061铝合金的自腐蚀电位增加了77 mV, 转化膜的腐蚀电流密度降低了约80%; 6061铝合金的耐蚀性能明显得到提高。

Abstract: The effects ammonium fluorosilicate, complexing agent and inhibitors on the corrosion resistance of fluorinetitanate conversion coating on the surface of 6061 aluminum alloy was studied by the single factor experiment. The optimal operation parameters were as follows: NaF 3 g/L, (NH4)2SiF6 4 g/L, (NaPO3)6 1.0 g/L, titanium salt 1.5 g/L, H2O2 1.5 ml/L, pH 5.0, normal temperature, 10 minutes. SEM, EDS and polarization curves were used to invstingate the morphology and corrosion resistance of the coating. The results showed that the fluorinetitanate conversion coating was composed of continuous and compact crystal particles. The corrosion potential increased about 77 mV and the corrosion current density decreased about 80%, the corrosion resistance was improved obviously.