【摘要】 用热重法 (TG)、X光衍射 (XRD)和带能谱的扫描电镜 (SEM EDS)研究了MgB2 在空气气氛中从室温到 1 0 0 0℃的热稳定性和氧化情况 .实验表明在 40 0℃MgB2 开始发生氧化 ,在70 0℃以上氧化强烈 .实验表明MgB2 的氧化是一比较复杂的过程 ,同时存在Mg和B的蒸发及MgO的形成 ,另外蒸发的Mg和O的反应可在晶粒表面形成直径为几十纳米左右 ,长几个微米的MgO晶须 ,生长的MgO晶须的形状受环境的很大影响 .用Freemen Carroll法和多个升温速率法估算了MgB2 的氧化活化能在 80kJ/mol左右 ,表明MgB2 是一较易氧化的化合物 .更多还原

【Abstract】 The thermal stability and oxidation of MgB-2 under air condition from room temperature to 1000℃ was investigated by thermogravimetry(TG), X-ray diffraction(XRD), scanning electron microscopy equipped with energy dispersion spectrum (SEM-EDS). The experiment shows that the obvious oxidation process begins at about 400℃ and becomes very strong when the temperature beyond 700℃. The experiment also shows that the oxidation of MgB-2 is a very complex process accompanying by the evaporation of boron and magnesium and formation of MgO. Long MgO whiskers with diameter in nanometer scale also appear, mostly on the grain surface, in the oxidation process due to the evaporated magnesium reaction with oxygen and the shape of the MgO whiskers strongly depends on the growing environment. The oxidation activation energy of MgB-2 is estimated to be about 80kJ/mol by using the Freeman-Carroll method and multi-heating rates method.更多还原