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目的 在前期研制的新型铝合金表面钛锆转化膜工艺配方的基础上,进一步探索该新型工艺配方在连续使用过程中的消耗规律.方法 通过在连续使用过程中对转化液中主要金属离子(钛、锆、M等)的含量测定分析,找出该成膜剂的消耗规律.采用电化学工作站和SEM对槽液连续使用过程中膜层的耐蚀性能及微观形貌进行表征.结果 转化液中的主要成膜成分钛、锆、M的消耗质量比例基本不变,为5:1:4.XPS分析显示,膜层主要由金属氧化物(TiO2、ZrO2、Al2O3、M2O5)、金属氟化物(ZrF4、AlF3)和金属有机络合物等组成.随着成膜的不断进行,膜层的耐蚀性能有所下降,自腐蚀电流密度由最初成膜时的0.11μA/cm2增加到1.24μA/cm2,但仍低于铝合金基体的自腐蚀电流密度(7.53μA/cm2).随着连续成膜,膜层表面的微观裂纹不断变宽,在连续成膜到第80片时,铝合金表面有的位置已经不能成膜.结论 钛锆转化液在连续使用过程中,转化液中的主要成膜成分按一定比例消耗,膜层的耐蚀性能随着连续成膜有所下降,因此有必要及时对转化液进行补加和校正.

The work aims to further explore consumption law of a novel titanium zirconium-based conversion solution formula used for aluminum alloy during continuous service based on the previously developed formula. The consumption law was studied by determining and analyzing content of main metal ions (titanium, zirconium, M, etc.) in conversion solution during continuous service. Then corrosion resistance and morphology of the conversion film were examined by using electrochemical workstation and SEM. Consumption mass ratio of the main film-forming components (Titanium, Zirconium and M) in the conversion solution was basically unchanged as 5:1:4. The analysis results of XPS showed that the conversion film was mainly composed of metal oxides (TiO2, ZrO2, M2O5 and Al2O3), metal fluoride (ZrF4, AlF3) and metal organic complex. As the film forming proceeded, corrosion resistance of the conversion film decreased, self-corrosion current density increased from 0.11μA/cm2 up to 1.24μA/cm2 but was still lower than that of aluminum alloy substrate (7.53μA/cm2). As the film forming continued, micro cracks on the film surface became wider, no film formed in certain spots on the surface of the aluminum alloy when the 80th specimen formed successively. During the continuous service of titanium zirconium-based conversion solution, consumption ratio of the main film-forming compo-nents is basically unchanged, corrosion resistance of the film declined with continuous film forming, and it is necessary to supplement and adjust the conversion solution timely.