(北京科技大學(xué) 新材料技術(shù)研究院 北京材料基因工程高精尖創(chuàng)新中心，北京 100083)
摘 要: 在100~600 ℃溫度區(qū)間對氫化脫氫(HDH)鈦粉進行預(yù)氧化處理，研究鈦粉表面狀態(tài)對其鈍化性能的影響規(guī)律及內(nèi)在機理。利用SEM、XRD、HRTEM、XPS等對HDH鈦粉顯微形貌、相組成、雜質(zhì)含量、表面氧化膜狀態(tài)等特性進行表征與分析。結(jié)果表明：HDH鈦粉中的氧含量隨著預(yù)氧化溫度的提高而增加，但預(yù)氧化處理后的HDH鈦粉抗環(huán)境氧化(鈍化)性能得到明顯改善；經(jīng)100 ℃、400 ℃預(yù)氧化處理鈦粉及未經(jīng)處理的鈦粉在干燥空氣中儲存60 d，鈦粉增氧率分別為24%、13%和50%，即預(yù)氧化鈦粉的鈍化效果比未經(jīng)預(yù)氧化處理的粉末更好。這是因為預(yù)氧化處理的鈦粉表面形成了更為致密且穩(wěn)定的TiO2薄膜，能有效降低氧原子向基體內(nèi)的擴散系數(shù)，從而延緩粉末氧化速率。然而，當(dāng)預(yù)氧化溫度高于500 ℃時，由于氧化膜中TiO2含量相對減少，導(dǎo)致氧化膜的熱穩(wěn)定性下降，其鈍化性能反而降低。
關(guān)鍵字: 鈦；鈦合金；粉末；鈍化；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
