EDTA对两种镁合金化学转化膜性能的影响
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摘要
研究了EDTA对镁合金锡酸盐、磷酸盐化学转化膜性能的影响。采用扫描电镜观察了两种化学转化膜的表面形貌,采用X射线衍射仪分析了两种化学转化膜的成分,并采用电化学工作站测试了两种化学转化膜的耐蚀性。结果表明:加入0.3g/L EDTA的锡酸盐化学转化膜晶粒细小、均匀,堆积十分紧密,无缝隙;加入2.0g/L EDTA的磷酸盐化学转化膜结晶细小、均匀,结构致密。锡酸盐化学转化膜的相组成为Mg、Al12Mg17和MgSn(OH)6;磷酸盐化学转化膜的相组成为Mg、Al12Mg17和Mn2Mg(PO4)2。通过对比可知,加入EDTA对锡酸盐化学转化膜耐蚀性的影响更为显著。
The effect of EDTA on properties of stannate chemical conversion coating and phosphate chemical conversion coating on magnesium alloy was studied.The surface morphology of two chemical conversion coatings was observed by scanning electron microscope,the composition was analyzed by X-ray diffractometer,and the corrosion resistance was tested by electrochemical workstation.Results showed that the stannate chemical conversion coating obtained with 0.3g/L EDTA was uniform and dense,with finer grains and no gaps.The phosphate chemical conversion coating obtained with 2.0g/L EDTA has the features of fine and even grains,and compact structure.The phase composition of stannate chemical conversion coating was Mg,Al12Mg17 and MgSn(OH)6,and that of phosphate chemical conversion coating was Mg,Al12Mg17 and Mn2Mg(PO4)2.By contrast,the effect of EDTA on the corrosion resistance of stannate chemical conversion coating was more remarkable.
The effect of EDTA on properties of stannate chemical conversion coating and phosphate chemical conversion coating on magnesium alloy was studied.The surface morphology of two chemical conversion coatings was observed by scanning electron microscope,the composition was analyzed by X-ray diffractometer,and the corrosion resistance was tested by electrochemical workstation.Results showed that the stannate chemical conversion coating obtained with 0.3g/L EDTA was uniform and dense,with finer grains and no gaps.The phosphate chemical conversion coating obtained with 2.0g/L EDTA has the features of fine and even grains,and compact structure.The phase composition of stannate chemical conversion coating was Mg,Al12Mg17 and MgSn(OH)6,and that of phosphate chemical conversion coating was Mg,Al12Mg17 and Mn2Mg(PO4)2.By contrast,the effect of EDTA on the corrosion resistance of stannate chemical conversion coating was more remarkable.
引文
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[2]霍宏伟,李华为,陈庆阳,等.AZ91D镁合金锡酸盐转化膜形成机理和腐蚀行为研究[J].表面技术,2007,36(5):1-3.
[3] HU B,SUN R,YU G,et al.Effect of bath pH and stabilizer on electroless nickel plating of magnesium alloys[J].Surface&coatings technology,2013,228(9):84-91.
[4] FORNO A D,BESTETTI M.Effect of the electrolytic solution composition on the performance of micro-arc anodic oxidation films formed on AM60B magnesium alloy[J].Surface&coatings technology,2010,205(6):1783-1788.
[5]邓永和.稀土镁合金研究现状与发展趋势[J].稀土,2009,30(1):76-79.
[6]陈先华,耿玉晓,刘娟.镁及镁合金功能材料的研究进展[J].材料科学与工程学报,2013,31(1):148-150.