摘要
通过同时加入Y和Ce获得了阻燃效果优异的Mg-Y-Ce阻燃镁合金,实现了镁合金在大气条件下的无保护熔炼,Mg-Y-Ce合金由工业纯Mg(99.9%,质量分数)、Mg-25%Y(质量分数)中间合金和纯Ce(99.5%,质量分数)在电阻炉中于保护性气氛(CO2+0.5%SF6)下熔配而成。AES(PHI550 ESCA/SAM)和XRD(X’Pert Pro MPD)表面分析结果表明:当Mg-3Y-4.5Ce阻燃镁合金在高温下暴露于大气中时,其表面膜为双层膜,外层主要由Y2O3组成,而内层Y和Ce含量极低,以Mg和MgO为主。基于高温氧化热力学分析,建立了Mg-Y合金在高温下的选择性氧化模型,获得了Mg-Y合金能够发生选择性氧化的Y浓度阈值(约为7%,质量分数)。分析了Ce在Mg-Y合金选择性氧化中的第三元素效应,Ce起到了"吸气剂"的作用,可以抑制氧向合金内部扩散,从而抑制Y元素的内氧化。
By adding Y and Ce high ignition-point temperature was realized in Mg-Y-Ce magnesium alloy,which can be melted in air without any protection.All the alloys,i.e.,Mg-Y and Mg-Y-Ce alloys were prepared by adding commercial purity Mg（99.9%,mass fraction）,Mg-25%Y（mass fraction） master alloy and pure Ce（99.5%,mass fraction） in a steel crucible under a cover gas mixture of CO2 and 0.5%SF6.AES（PHI550 ESCA/SAM） and XRD（X＇Pert Pro MPD） analysis of the oxide scale reveals that,when the ignition-proof Mg-3Y-45Ce alloy is exposed in air at high temperature the oxidation film includes two layers.The outer layer consists of Y2O3,and the inner layer consists of Mg and MgO with a little Y and Ce.Based on the analysis of the high temperature oxidation thermodynamics,the model of the selective oxidation for Mg-Y alloys at high temperature was established,and the critical content of Y for the selective oxidation of Mg-Y alloys was obtained to be about 7%（mass fraction）.The third element effect of Ce in the selective oxidation of Mg-Y alloys was analyzed.Ce plays a role of ＂getter＂ which inhibits the diffusion of O to internal alloy,so as to inhibit the inner oxidation of Y.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2011年第11期2799-2804,共6页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(50901048)
山西省高等学校优秀青年学术带头人支持计划
山西省基础研究计划项目(2010021022-5)
西北工业大学凝固技术国家重点实验室开放基金资助项目(SKLSP201003)
关键词
阻燃镁合金
氧化膜
选择性氧化
第三元素效应
ignition-proof magnesium alloy
oxidation film
selective oxidation
the third element effect
