LIU Gang*,ZHAO Yazhong,ZHAO Ke,et al.Effect of Phytic Acid Treatment on Corrosion Properties of LZ91 Magnesium Lithium Alloy[J].Plating & Finishing,2022,(5):28-32.[doi:10.3969/j.issn.1001-3849.2022.05.005]
植酸处理对LZ91镁锂合金腐蚀性能的影响
- Title:
- Effect of Phytic Acid Treatment on Corrosion Properties of LZ91 Magnesium Lithium Alloy
- Keywords:
- LZ91 magnesium lithium alloy; phytic acid treatment; conversion time; morphology of conversion film; corrosion performance
- 分类号:
- TG178
- 文献标志码:
- A
- 摘要:
- 对厚度 3 mm 的 LZ91 镁锂合金在不同转化时间下进行了植酸化学转化处理。采用扫描电子显微镜、 X 射线能谱仪、电化学工作站等设备对不同植酸转化时间生成的转化膜的形貌、转化膜成分、腐蚀性能和成膜工艺进行了测试和分析。结果表明,当植酸浓度、植酸溶液 pH 值和转化温度分别保持 2 mL/L 、 6 和 55 °C 不变,转化时间在 2 ~ 15 min 之间时, LZ91 镁锂合金表面生成的转化膜良好,转化膜上生成了难溶的白色颗粒状锌的螯合物。随着植酸处理转化时间的增加,转化膜的龟裂纹呈现出逐渐由浅变深的趋势,转化膜厚度呈现出先增大后减小的现象, LZ91 镁锂合金植酸处理后的耐腐蚀性能先上升后下降,当转化时间为 5 min 时, LZ91 镁锂合金植酸处理后的耐腐蚀性能最好,其自腐蚀电流密度最小为 3.76×10 -5 A/cm 2 ,相比植酸处理前的自腐蚀电流密度下降了 2 个数量级,此时为植酸处理 LZ91 镁锂合金形成转化膜的最佳时间。
- Abstract:
- : LZ91 magnesium lithium alloy with a thickness of 3 mm was treated with phytic acid chemical conversion method under different conversion times. The morphology , composition , corrosion performance and film-forming process of the conversion film formed at different phytic acid conversion time were tested and analyzed by scanning electron microscope , X-ray energy spectrometer and electrochemical workstation. The results show that when the phytic acid concentration , pH value of phytic acid solution and conversion temperature remain unchanged at 2 mL/L , 6 and 55 °C respectively , and the conversion time is between 2 and 15 min , the conversion film formed on the surface of LZ91 magnesium lithium alloy is good , and the insoluble white granular zinc chelate is formed on the conversion film. With the increase of phytic acid treatment conversion time , the tortoise crack of conversion film gradually changes from shallow to deep , the thickness of conversion film first increases and then decreases , and the corrosion resistance of LZ91 magnesium lithium alloy after phytic acid treatment first increases and then decreases. When the conversion time is 5 min , the corrosion resistance of LZ91 magnesium lithium alloy after phytic acid treatment is the best , and its self-corrosion current density is the minimum of 3.76×10 -5 A/cm 2 , compared with the self-corrosion before phytic acid treatment , its value decreased by 2 orders of magnitude , which indicates that 5 min is the best time for phytic acid treatment of LZ91 magnesium lithium alloy to form conversion film.
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备注/Memo
收稿日期: 2021-09-23 修回日期: 2021-10-12 作者简介: 刘刚( 1982 ―),男,博士,讲师,主要研究方向:轻合金塑性成型及连接技术, email : liugang@nyist.edu.cn 基金项目: 河南省高等学校重点科研项目( 20A430020 );湖北省自然科学基金项目( 2019CFC909 );南阳理工学院博士科研启动项目( 510109 );南阳理工学院交叉科学研究项目( 520067 )