AZ31镁合金表面钼酸盐转化膜的制备与耐蚀性能

发布时间：2018-12-14 03:52

【摘要】：以Na2Mo O4为主盐,与氧化剂H2O2、成膜促进剂NaF和Na2Si O3一起组成化学转化液,在AZ31镁合金表面制备钼酸盐转化膜,利用扫描电镜和X线光电子能谱仪分析转化膜的形貌和组成,通过电化学阻抗测试研究转化膜在3.5%Na Cl溶液中的腐蚀行为,并讨论成膜机理,研究转化液中Na2Mo O4浓度与p H以及成膜温度和时间对薄膜结构与耐腐蚀性能的影响。结果表明:转化液的优化组成为0.2 mol/L Na2Mo O4+0.12 mol/L NaF+0.014mol/L Na2Si O3+0.012 mol/L H2O2;优化工艺条件为p H=5,温度60℃,转化时间30 min;转化膜为黄棕色,主要由Mg Mo O4,Mg F2,Mo O2,Mo O3和Mg Si O3组成,转化膜宏观上完整均匀,存在网状微裂纹;钼酸盐转化膜能有效提高AZ31镁合金的耐腐蚀性能,对基体合金有一定的保护作用。
[Abstract]:The molybdate conversion film was prepared on the surface of AZ31 magnesium alloy by using Na2Mo O 4 as main salt, oxidant H 2O 2, film forming accelerator NaF and Na2Si O 3. The morphology and composition of the conversion film were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. The corrosion behavior of the conversion film in 3.5%Na Cl solution was studied by electrochemical impedance measurement, and the mechanism of film formation was discussed. The effects of Na2Mo O 4 concentration and pH in the conversion solution, film forming temperature and time on the structure and corrosion resistance of the film were studied. The results show that the optimum composition of the conversion solution is 0.2 mol/L Na2Mo O 4 0.12 mol/L NaF 0.014mol/L Na2Si O 3 0.012 mol/L H 2O 2, the optimum process conditions are: pH 5, temperature 60 鈩，

本文编号：2377868