铍的高温氧化行为及特性研究

在不同温度下对金属铍（Be）进行热氧化，采用热重、AES和SEM对Be的热氧化过程、氧化后表面状态、微区成分和氧化层厚度进行表征和分析，探讨了不同温度下Be的氧化行为和氧化特性。结果表明：室温～400 ℃范围内，Be样品的氧化增重主要服从抛物线规律；400～900 ℃范围内，主要呈线性变化。在较低温度下，Be表面形成的钝化层具有良好的保护作用，比较耐蚀。高温对Be样品的氧化影响较大，认为600 ℃以下Be的氧化主要受Be原子向表面的热扩散控制；800 ℃以上，氧通过晶界和孔洞扩散进入材料体内、氧化膜受热膨胀以及应力作用开裂等，导致Be发生严重的氧化腐蚀。

High Temperature Oxidation Behavior and Characteristic of Beryllium

The thermal oxidation of beryllium was investigated at different tempera-tures.The oxidation process,surface state after oxidation,micro-area composition and oxidation thickness were characterized and analyzed by thermogravimetry,AES and SEM.The oxidation behavior and characteristics of beryllium at different temperatures were also discussed.The results show that in the range of room temperature to 400 ℃, the oxidation weight gain of beryllium mainly follows parabolic law,and in the range of 400 ℃ to 900 ℃,the oxidation rate generally obeys linear change.At lower tempera-tures,the passivation layer formed on the surface of beryllium shows a good protective effect,which is very resistant to corrosion.The oxidation rate of beryllium is highly affected by higher temperatures.Below 600 ℃,the oxidation rate seems to be limited by the diffusion of beryllium atoms towards the surface.Above 800 ℃,oxygen diffuses into the material through the grain boundaries and pores,and oxide films crack during thermal expansion and stress action,which results in serious oxidation corrosion.