(1. 太原理工大學 材料科學與工程學院，太原 030024；
2. 新材料界面科學與工程教育部重點實驗室，太原 030024)
摘 要: 通過同時加入Y和Ce獲得了阻燃效果優(yōu)異的Mg-Y-Ce阻燃鎂合金，實現(xiàn)了鎂合金在大氣條件下的無保護熔煉，Mg-Y-Ce合金由工業(yè)純Mg(99.9%，質(zhì)量分數(shù))、Mg-25%Y(質(zhì)量分數(shù))中間合金和純Ce(99.5%，質(zhì)量分數(shù))在電阻爐中于保護性氣氛(CO2+0.5%SF6)下熔配而成。AES(PHI550 ESCA/SAM)和XRD(X’Pert Pro MPD)表面分析結果表明：當Mg-3Y-4.5Ce阻燃鎂合金在高溫下暴露于大氣中時，其表面膜為雙層膜，外層主要由Y2O3組成，而內(nèi)層Y和Ce含量極低，以Mg和MgO為主。基于高溫氧化熱力學分析，建立了Mg-Y合金在高溫下的選擇性氧化模型，獲得了Mg-Y合金能夠發(fā)生選擇性氧化的Y濃度閾值(約為7%，質(zhì)量分數(shù))。分析了Ce在Mg-Y合金選擇性氧化中的第三元素效應，Ce起到了“吸氣劑”的作用，可以抑制氧向合金內(nèi)部擴散，從而抑制Y元素的內(nèi)氧化。
關鍵字: 阻燃鎂合金；氧化膜；選擇性氧化；第三元素效應
（1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Key laboratory of Interface Science and Engineering in Advanced Materials, of Ministry of Education,
Taiyuan University of Technology, Taiyuan 030024, China）
Abstract: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.
Key words: ignition-proof magnesium alloy; oxidation film; selective oxidation; the third element effect
