氧化膏处理对2024-T3铝合金表面性能的影响

针对铝合金蒙皮表面涂层修复对基材局部现场氧化处理的需求,研究了膏状氧化材料的调制方法,并探讨了氧化膏在2024-T3铝合金表面的成膜性能。通过扫描电镜、能谱、体视显微镜、点滴、电化学、接触角测试以及拉伸剪切实验考察了氧化膜的形貌和组成、耐蚀性能及粘接性能。实验表明,室温下铝合金表面经氧化膏处理后可快速生成氧化膜,膜层具有一定的微观孔洞结构,主要包含Al、F、Cr、O等元素;膜层耐蚀性与阿洛丁氧化液处理效果相近,与未氧化试样相比腐蚀电压由-0.898 V升至-0.880 V,腐蚀电流密度由2.582×10~(-5)A/cm~2降至3.334×10~(-7)A/cm~2,阻抗值由1.556×10~3Ω/cm~2增至1.347×10~5Ω/cm~2;表面自由能和粘附功分别由32.7 m J/cm~2和36.3 m J提高到55.7 m J/cm~2和109.7 m J,拉伸剪切强度由11.7 MPa提升为15.0 MPa,结果表明氧化膜的形貌和组成有助于获得更好的界面结合力并改善基材的粘接性能。

Influence on surface performance of 2024-T3 aluminum alloy processed with oxidising paste

Oxidising paste was prepared for in-situ local oxidation treatment of coatings on aluminum alloy skin surface and its film-forming performance on 2024-T3 aluminum alloy was studied.Morphology and chemical composition,corrosion resistance,and adhesive performance of the oxidation film were investigated by SEM,EDS,stereomicroscope,drop test,electrochemistry test,contact angle and tension loading method.The results show that oxidation film can be obtained rapidly on aluminum alloy surface after treated by oxidising paste,and the film has mieroscopic pore structure,including Al,F,Cr,O,etc.Corrosion resistance of the film is similar to that gained by Alodine solution.Compared to the bare sample,corrosion potential increases from-0.898 V to-0.880 V,corrosion current density decreases from 2.582 × 10-5 A/cm2 to 3.334 × 10 7 A/cm2,and impedance improves from 1.556 × 10s Ω/cm2 to 1.347 × 105 Ω/cm2.Surface free energy and the work of adhesion rise from 32.7 mJ/cm2 and 36.3 mJ to 55.7 mJ/cm2 and 109.7 mJ,respectively.Strength properties of adhesive in shear is promoted from 11.7 MPa to 15.0 MPa.The results indicate that morphology and chemical composition of the oxidation film can enhance interface bonding strength and adhesive performance.