阻燃钛合金的高温氧化行为

High Temperature Oxidation Behaviour of a Fire-Resistant Titanium Alloy

研究了阻燃钛合金ＡｌｏｙＣ在６００℃～９００℃范围内的氧化行为。氧化增重试验及ＸＲＤ，ＳＥＭ，ＸＰＳ和ＥＰＭＡ的分析结果表明，在７００℃以上，氧化速度随温度升高而快速增长，９００℃的氧化速度近似于线性规律，氧化增重比常规高温钛合金和钛铝金属间化合物大得多。其原因主要是：（１）由于Ｃｒ含量较低，以及Ｃｒ同Ｏ的亲合力小于Ｔｉ同Ｏ的亲合力，在６００℃以上表面不能形成保护性Ｃｒ２Ｏ３膜；（２）在７００℃以上，由于Ｖ２Ｏ５氧化物的挥发作用，在金属－氧化物界面产生Ｖ元素浓度的梯度分布。

The oxidation behaviour of the fire-resistant titanium alloy, Alloy C, over a range of 600℃ to 900℃ is studied by weight gain measurements and XRD, SEM, XPS, EPMA analyses The results show that the oxidation rate above 700℃ increases rapidly with increasing temperature, and at 900℃ is approximately linear The weight gain of Alloy C is much larger than those of conventional high temperature titanium alloys and the titanium aluminides The main reason for this is that: (1) A protective Cr2O3 scale does not form on the surface of Alloy C above 600℃, as consequence of the low Cr content and smaller affinity of Cr for O than that of Ti for O (2) A concentration gradient of the element V exists at the metal-oxide interfaces and porous structure forms in the scale due to volatilization of the deleterious oxide V2O5 above 700℃