(北京科技大学 新材料技术研究院 北京材料基因工程高精尖创新中心，北京 100083)
摘 要: 在100~600 ℃温度区间对氢化脱氢(HDH)钛粉进行预氧化处理，研究钛粉表面状态对其钝化性能的影响规律及内在机理。利用SEM、XRD、HRTEM、XPS等对HDH钛粉显微形貌、相组成、杂质含量、表面氧化膜状态等特性进行表征与分析。结果表明：HDH钛粉中的氧含量随着预氧化温度的提高而增加，但预氧化处理后的HDH钛粉抗环境氧化(钝化)性能得到明显改善；经100 ℃、400 ℃预氧化处理钛粉及未经处理的钛粉在干燥空气中储存60 d，钛粉增氧率分别为24%、13%和50%，即预氧化钛粉的钝化效果比未经预氧化处理的粉末更好。这是因为预氧化处理的钛粉表面形成了更为致密且稳定的TiO2薄膜，能有效降低氧原子向基体内的扩散系数，从而延缓粉末氧化速率。然而，当预氧化温度高于500 ℃时，由于氧化膜中TiO2含量相对减少，导致氧化膜的热稳定性下降，其钝化性能反而降低。
关键字: 钛；钛合金；粉末；钝化；氧化；氧化膜
（Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The influence of surface state of Ti powders on its passivation performance and the intrinsic mechanism were investigated by pre-oxidation treatment of hydride-dehydride (HDH) Ti powders at 100-600 ℃. The micro-morphology, phase composition, impurity content and surface oxide film of HDH Ti powders were characterized and analyzed by SEM, XRD, HRTEM and XPS. The results show that the oxygen content of HDH Ti powders increases with the increase of pre-oxidation temperature. In addition, the environmental oxidation (passivation) performance of HDH Ti powders after pre-oxidation treatment is significantly improved, since the oxygen increment is 24%, 13% and 50% for the Ti powders after being pre-oxidation treated at 100 ℃ and 400 ℃ as well as the untreated Ti powders stored in dry air for 60 d, respectively. This indicates that the passivation effect of pre-oxidation Ti powders is better than that of raw powders. This is because a more densified and stable oxide film is formed on the surface of pre-oxidized Ti powders, which can effectively reduce the diffusion coefficient of oxygen atoms into the matrix, lowering its oxidation rate. However, when the pre-oxidation temperature is higher than 500 ℃, the TiO2 content of the oxide film is relatively reduced. This results in a decrease in the thermal stability of the oxide film, which in turn reduces its passivation performance.
Key words: titanium; titanium alloys; powder; passivation; oxidation; oxide film
