氢氧焰燃烧制备纳米Al_2O_3颗粒及其分散性能

Preparation of Nano-Al_2O_3 Particles via H_2/Air Flame Synthesis and Their Dispersion Performance

利用多重射流氢氧燃烧反应器,以AlCl3为前驱体制备了具有不同形貌和晶型结构的Al2O3纳米颗粒,表征了其形貌、晶型结构、比表面积、粒径分布等性能,考察了火焰燃烧形式和反应区最高温度等因素对颗粒性能的影响规律.结果表明,随反应温度升高,Al2O3粒径不断长大,形貌从具有链状结构的不规则颗粒逐渐转变为分散性良好的球形颗粒;同时随反应温度升高和在高温火焰中停留时间延长,晶型由单纯γ相逐渐转变为δ和δ*相.产品纳米Al2O3颗粒具有较强亲水性,其分散液具有较好的稳定性.探讨了高温快速反应过程中颗粒和团聚体的生长机理,最终产物的粒径和团聚体形貌取决于各主要影响条件的相互竞争.

Nano-Al2O3 particles were prepared via H2/air flame synthesis in a multi-jet reactor with anhydrous AlCl3 as precursor,the morphology,structure,crystallinity,size and specific surface area of the prepared nanoparticles were investigated,and the influences of flame configuration and maximum temperature in the reaction zone on their properties characterized.The results showed that the size of particles increased with the flame temperature increasing,and their morphology changed from irregular chain-like aggregates to well dispersed spherical nanoparticles.At the same time,a simple γ-phase was gradually transformed to δ and δ＊ phases.Dispersion of nano-Al2O3 particles had strong stability.The growth mechanism of particles and aggregates at rapid high-temperature reaction was discussed.The morphology and particle size of prepared nanoparticles depended on the competition among the key influential factors.