纳米镁铝尖晶石粉体的低温燃烧合成与表征

以硝酸盐和蔗糖为原料,利用低温燃烧合成制备纳米镁铝尖晶石(MgAl_2O_4)粉体,研究了不同煅烧温度、气氛以及加热速率等因素对纳米MgAl_2O_4粉体特性的影响.结果表明:随着前驱体煅烧温度的升高,纳米MgAl_2O_4晶粒尺寸逐渐增大;在O2环境中煅烧前驱体可以降低纯MgAl_2O_4相的形成温度,促进反应物质扩散、增大晶粒尺寸.在快速升温、蔗糖与硝酸盐物质的量比为2∶1以及通入O2的条件下,在400℃下煅烧生成MgAl_2O_4相,700℃时得到单相MgAl_2O_4纳米粉体.低温燃烧合成制备纳米MgAl_2O_4粉体结晶度高、晶粒尺寸细小,呈松散的软团聚态,有利于降低MgAl_2O_4陶瓷致密化烧结温度.

Low Temperature Combustion Synthesis and Characterization of Nanocrystalline Magnesium Aluminum Spinel (MgAl2O4) Powders

Nanocrystalline magnesium aluminate spinel (MgAl₂O₄) powders were prepared by a low temperature combustion synthesis method using nitrates and sucrose as starting materials， the characteristics of the as-synthesized powders were investigated in terms of heating temperature， environmental atmosphere and heating rate. The results show that particle sizes of MgAl₂O₄ spinel powder increase with the heating temperature of polymer precursors. When the precursors are heated in O₂ atmosphere， the reduced formation temperature of pure MgAl₂O₄ phase and accelerated reactive species diffusion along with enlarged particle sizes can be achieved. Under the conditions of fast heating， 2∶1 molar ratio of sucrose to nitrates and O₂ atmosphere， the formation temperature of MgAl₂O₄ phase is at 400℃ and further pure single phase is obtained at 700℃. The highly crystalline， soft agglomerated nano-sized MgAl₂O₄ powders are in favor of decreasing sintering temperature of high dense MgAl₂O₄ ceramics.