研究了熔态Mg在Air/SF6保护气氛中形成的表面膜特征.随着镁液在保护气氛中暴露时间的增加,表面膜中F原子分数逐渐增加,而O的原子分数基本不变.因此认为保护性表面膜形成后,主要为F和Mg发生反应.部分近表面区域场发射SEM断面图中有多个不连续的白亮富F(约为74%原子分数)小半圆区域,而富F的小半圆亮区之间F含量显著降低(约为4.98%);部分为一条厚度不均匀的白亮带,其中F原子分数也很不均匀.随着暴露时间的增加,表面的结晶粒度逐渐增加.冷却凝固后的表面有很多裂纹,这些裂纹的形成可能是由于表面MgO膜疏松,晶粒不断长大收缩,快速凝固过程中,MgO膜下面的镁液凝固收缩而形成.
参考文献
| [1] | Couling S L;BENNETT F C;LEONTIS T E .Melting magnesium under air/SF6 protective atmospheres[J].Light Metal Age,1977,35:12-21. |
| [2] | COULING S L.Use of air/CO2/SF6 gas mixtures for improved protection of molten magnesium[A].Norway:Oslo,1979:54-57. |
| [3] | Cashion S P .The use of sulphur hexafluoride (SF6) for protecting molten magnesium[D].QueenslandAustralia:Dept of Mining Minerals and Materials EngineeringUniversity of Queensland,1998. |
| [4] | Cashion S P;RICKETTS N J;HAYES P C .Characterisation of protective surface films formed on molten magnesium protect-ed by Air/SF6 atmospheres[J].Journal of Light Metals,2002,2:37-42. |
| [5] | Cashion S P;RICKETTS N J;HAYES P C .The mechanism of protection of molten magnesium by cover gas mixtures containing sulphur hexafluoride[J].Journal of Light Metals,2002,2:43-47. |
| [6] | Pettersen G.;Ovrelid E.;Tranell G.;Fenstad J.;Gjestland H. .Characterisation of the surface films formed on molten magnesium in different protective atmospheres[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2002(1/2):285-294. |
| [7] | AARSTAD K.Various techniques to study the surface of magnesium protectedby SF6[A].Kaplan:Howard I,2003:5-10. |
| [8] | 中国机械工程学会铸造专业学会.铸造手册:铸造非铁合金[M].北京:机械工业出版社,1993 |
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