熔融铝对Al活化TiO2的反应自发渗透

摘要

研究Al活化TiO2(锐钛矿型)的反应自发渗透.为了进行活化,先将纯Al粉与TiO2混合,再将其压制成预制棒,然后密封于6060铝合金模具中.活化和渗透试验在6060铝合金浴中完成,时间1 h.作为对比,在相同的温度和时间条件下,在氩气保护环境中进行烧结试验.X射线衍射分析表明,就Al与TiO2的反应活化而言,Al密封环境优于氩气保护.试验发现,TiO2与Al的混合比和温度影响渗透和反应动力学,在渗透过程中起着主要的作用.渗透后观察到3种主要的显微结构:完全渗透、部分渗透并形成裂纹和无渗透.基于反应动力学和反应导致的局部体积变化,解释这些显微结构的形成原因.最后,研究发现,为了获得总体良好的自发渗透,TiO2与Al混合比(体积比)约3:7、渗透温度约900℃ 最为适宜.%The reactive spontaneous infiltration of Al-activated TiO2 (anatase) was investigated. Pure Al powder was blended with TiO2 for activation. They were compacted into the preform and then sealed within 6060 alloy mould. The activation and infiltration were carried out in 6060 alloy bath for 1 h and comparative sintering experiments were carried out in an argon protected environment under the same conditions of temperature and duration. X-ray diffraction analysis proved that the Al sealed environment was superior to the argon protection on activating the reaction between Al and TiO2. The blending ratio of TiO2 to Al and the temperature were found to play the most important role in infiltration by affecting infiltration and reaction kinetics. Three main types of microstructures were observed after infiltration: full infiltration, partial infiltration with the formation of cracks and no infiltration. The formation of these microstructures was explained on the basis of reaction kinetics and local volume changes due to the reactions. Ultimately, it is found that to obtain an overall good spontaneous infiltration, a TiO2 to Al blending ratio around 3:7 in volume and an infiltration temperature around 900 ℃ are the most suitable.