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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.
The Al2O3 hydrogels with different morphologies and crystal structures were prepared by multi-jet hydrogen-oxygen combustion reactor with AlCl3 as precursor. The morphology, crystal structure, specific surface area and particle size distribution were characterized. Flame combustion mode and the maximum temperature of the reaction zone on the properties of the particles.The results show that with the increase of the reaction temperature, the particle size of Al2O3 grows continuously and the morphology gradually changes from the irregular particles with chain structure to the good dispersibility Of the spherical particles; at the same time with the reaction temperature and residence time in the flame at high temperature, the crystalline form gradually transformed from simple γ phase δ and δ * phase nano-Al2O3 particles have strong hydrophilic properties, the dispersion has more Good stability.The mechanism of the growth of particles and agglomerates during rapid reaction at high temperature was discussed.The particle size and aggregate morphology of the final product were determined by the competition of the main influence conditions.