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在600～900℃温度下,0.5～72 h时间范围内空气气氛下对Ti6Al7Nb进行热氧化,根据增重曲线计算其氧化动力学规律,利用XRD、XPS分析表面氧化层的相组成、成分和价态,并以Ti6Al4V合金做为比照。结果表明,Ti6Al7Nb合金较Ti6Al4V合金抗氧化能力更强。同等氧化条件下,Ti6Al7Nb合金的氧化速率常数(k)更小。对短时间(1 h)氧化的样品的表面分析显示:各合金元素均以最高价态或稳定价态存在,其中Al和V被富集,而Nb则贫化;另外,Ti6Al7Nb合金和Ti6Al4V合金氧化层主要由金红石型TiO2(R-TiO2)组成,Al2O3相仅出现在900℃Ti6Al4V合金样品中。
Ti6Al7Nb was thermally oxidized in air atmosphere at temperature of 600-900 ℃ in 0.5-72 h. The oxidation kinetics of Ti6Al7Nb was calculated according to the weight gain curve. The phase composition, composition and valence of the surface oxide were analyzed by XRD and XPS. State, and to Ti6Al4V alloy as a reference. The results show that Ti6Al7Nb alloy is more resistant to oxidation than Ti6Al4V alloy. Under the same oxidation conditions, the oxidation rate constant (k) of Ti6Al7Nb alloy is smaller. The surface analysis of samples oxidized in a short period of time (1 h) showed that all the alloying elements existed in the highest valence state or the stable valence state, in which Al and V were enriched and Nb was depleted. In addition, Ti6Al7Nb alloy and Ti6Al4V alloy The oxide layer mainly consists of rutile TiO2 (R-TiO2), and the Al2O3 phase only appears in the sample of Ti6Al4V alloy at 900 ℃.