铝合金磷酸阳极化及胶接性能分析

The Phosphoric Acid Anodizing of Aluminum Alloys for Adhesive Bonding

采用磷酸阳极化方法对铝合金试片进行了处理并测试了其粘接性能。测试了铝合金试片表面预处理和阳极化后的性能,研究了阳极化工艺参数对接头胶接性能的影响,观察了磷酸阳极化处理后的铝合金试片的表面形貌和其与胶粘剂粘接时的粘接界面,分析了其粘接拉剪破坏的失效模式。结果表明,金属表面预处理和阳极化不影响铝合金试片的性能。阳极化处理不仅改变了铝合金胶接表面的材料组成,而且在铝合金试片粘接表面形成厚度可达90μm、凹凸不平的、多孔的膜。胶接时胶粘剂能够渗透进入阳极化铝合金表面孔洞并在粘接界面形成厚度约为20μm的过渡层。阳极化处理提高了铝合金粘接副之间的拉剪强度,其最大拉剪强度为45.99MPa,其接头拉剪破坏模式为混合破坏,而未阳极化的铝合金胶接副的拉剪强度只有13.59 MPa。

The aluminum alloy for adhesive bonding was anodized in the aqueous solutions of phosphoric acid and the adhesive property was investigated. The mechanical properties of aluminum alloy samples were measured after pre-treating and anodizing. The effects of the anodizing parameters on the adhesion were studied. The surface microstructure of anodized aluminum and its bonding interface with the adhesive were observed. The failure mode was examined. It is shown that both the anodizing and the pre-treating, in which the aluminum alloy was processed by the acid and alkaline aqueous solutions, have an effect on the properties of the samples. The anodizing not only changes the surface constitutes but also produces the porous and microrough film, whose thickness is about 90μm. A transition layer between the alloy and the adhesive, whose thickness is about 20μm, is formed when the adhesive penetrates into the film during bonding. The maximum lap shear strength of the anodized sample is 45. 99MPa, while the lap shear strength of the non-anodized sample is 13.59MPa. The adhesion is promoted greatly and the mixed failure mode is found.