AC7A铝合金表面硬质氧化膜制备及性能研究

摘要

阳极氧化是提高铝镁合金表面硬度的一种有效方法.在AC7A铝合金表面制备硬质阳极氧化膜,研究了阳极氧化时间、电流密度、工作液温度以及阳极氧化溶液中硫酸浓度等工艺参数对氧化膜显微硬度及耐蚀性的影响,并对工艺参数进行了优化.结果表明,优化后的工艺参数θ为-6℃,氧化t为50 min,Ja为1～6A/dm2,240g/lL硫酸,硬质阳极氧化膜硬度可达480 HV,有效强化了轮胎模具花纹块配合表面的硬度,提高了其使用寿命,可以达到工件硬质阳极氧化膜硬度的要求,且氧化膜颜色深而均匀.最佳工艺参数下制备的氧化膜在240h盐雾试验中,耐中性盐雾腐蚀性能明显提高.%Anodic oxidation is an effective method to improve the surface hardness of aluminium-magnesium alloy.The hard anodic oxidation films has been prepared on the surface of the AC7A aluminum alloy and the effects of different parameters on the hardness of the films are discussed.Parameters includinganodic oxidation time,temperature,current density and H2SO4 fraction in oxidation solution have been optimized.The hardness of the films is studied by FM800 hardness tester.The optimized parameters includes a temperature of-6 ℃,current density of 1 ～ 6 A/dm2,a positive and an oxidation time of 50 min,H2SO4 fraction in oxidation solution of 240 g/L.The parts processed by new techniques meet the hard anode oxidation's requirement.In the 240 h salt spray test,neutral salt spray corrosion resistance is improved significantly.