电解液对 2A12 铝合金硬质阳极氧化膜层性能的影响

目的对硫酸、混合酸电解液体系中制备的2A12铝合金硬质阳极氧化膜层性能进行研究,找出混合酸电解液体系对2A12铝合金硬质阳极氧化过程的影响机理,为改善膜层的耐蚀性能提供一种思路。方法通过对膜层厚度、显微硬度、微观形貌、极化曲线、交流阻抗试验结果进行分析,研究不同电解液对2A12硬质阳极氧化膜层性能的影响。结果在有机酸的活性吸附作用下,混和酸电解液解决了硫酸电解液制备2A12铝合金硬质阳极氧化膜存在的厚度、硬度不均匀及烧蚀现象,制备的膜层厚度范围为35~38μm,硬度范围为386~407HV0.05,具有厚度和硬度分布均匀、离散性小的特点。极化曲线及电化学交流阻抗分析表明,混合酸电解液体系中制备的2A12铝合金硬质阳极氧化膜层未进行封孔处理时,膜层的自腐蚀电位为-619.93 m V,阻挡层电阻为1.4×105Ω·cm2;封孔处理后,膜层的自腐蚀电位为-74.69m V,阻挡层电阻为2.376×106Ω·cm2。这说明封孔处理能够改善阻挡层的质量,显著提高膜层的耐腐蚀性能。结论采用混合酸电解液体系能够稳定制备出2A12铝合金硬质阳极氧化膜层,制备的膜层应进行封孔处理。

Influence of Electrolyte on the Properties of Hard Anodic Oxide Coating on 2A12 Aluminium Alloy

Objective To study the properties of hard anodic oxidation coatings on 2A12 aluminum alloy prepared in the electro-lyte of sulphuric acids and hybrid acids separately,in order to find out the influencing mechanism of hybrid acids on hard anodic ox-idation process of 2A12 aluminum alloy, and provide method to enhance the coating corrosion resistance. Methods The properties of hard anodic oxide coatings prepared in different electrolytes were analyzed and characterized by thickness, micro-hardness, SEM morphology, polarization curve and AC impedance spectroscopic to investigate the influence of different electrolytes on the perform-ance of hard anodic oxidation coatings on 2A12 aluminum alloy. Results The phenomenon of hard anodic oxide coatings on 2A12 aluminum alloy prepared in electrolyte of sulphuric acids such as ablation, non-uniform distribution of thickness and micro-hardness can be resolved by active adsorption of organic acids in electrolyte of hybrid acids, and the thickness distribution range was 35~38 μm, the micro-hardness distribution range was 386~407HV0. 05. The polarization curve and the EIS analysis showed that the cor-rosion potential of unsealed and sealed coating was -619. 93 mV and -74. 69 mV separately, the barrier layer resistance of un-sealed and sealed coating was 1. 4×105 Ω·cm2 and 2. 376×106 Ω·cm2 separately, which indicated that corrosion resistance can be enhanced and improved by sealing. Conclusion Hard anodic oxide coatings on 2A12 aluminum alloy can be stably prepared in electrolyte of hybrid acids, and the coating should be sealed.