7075铝合金表面HEDP阳极氧化工艺参数影响分析

Analysis on the Effects of Process Parameters of HEDP Anodic Oxidation on the Surface of 7075 Aluminum Alloy

以HEDP(羟基乙叉二膦酸)作为铝合金阳极氧化的电解液对合金进行处理,可以显著提升零件的防腐性能,有助于在海洋条件下使用。通过正交试验并结合单因素试验确定了HEDP阳极氧化的最佳工艺参数:HEDP浓度0.3 mol/L,温度20~30℃,电流密度0.83 A/dm^(2),氧化时间60 min,分析了各工艺参数对膜层结构的影响。根据最佳工艺参数阳极氧化膜的形貌分析得出阻挡层的厚度,并与硫酸阳极化阻挡层进行了厚度对比。

The anodic oxidation treatment on aluminum alloy using HEDP(hydroxyethylidene diphosphonic acid) as the electrolyte additive could significantly improve the corrosion resistance of the parts and be helpful for their use in marine conditions. The optimum process parameters of HEDP anodic oxidation were determined by orthogonal test and single factor test: a HEDP concentration of 0.3 mol/L, a temperature of 20~30 ℃, a current density of 0.83 A/dm^(2), and an oxidation time of 60 min. Moreover, the influences of various process parameters on the film microstructure were analyzed. Based on the morphology of the anodic oxide coating prepared using the optimum process parameters, the thickness of blocking layer was obtained, which was further compared with the thickness of sulfuric acid anodic blocking layer.