微波辅助溶液燃烧法制备MgAl_2O_4粉体

Synthesis of MgAl_2O_4 powders by microwave-assisted combustion

将硝酸镁、硝酸铝、尿素按物质的量比为1 2 6.66制得透明混合前驱液,用低温燃烧技术与微波加热技术相结合的方法制备了高纯度、低团聚的镁铝尖晶石(MgAl2O4)粉体。研究了燃烧反应过程中,微波输出功率(200、400、600、700 W)对Mg Al2O4粉体晶体结构、形貌及比表面积的影响。结果表明:微波高效加热方式导致燃烧反应瞬间产生大量气体,促进了Mg Al2O4超细颗粒的形成。同时,随着微波输出功率的增加,尿素氧化加速,利于MgAl2O4晶粒的生长发育。在微波功率700W,微波时间2 min的条件下,可制备结晶完整,粒度分布均匀(平均晶粒尺寸为56.03 nm)的Mg Al2O4粉体。

High purity,low agglomeration MgAl2O4 powders were synthesized by the microwave-assisted low temperature combustion method using magnesium nitrate,aluminum nitrate and urea （mass ratio of 1 2 6.66） as starting materials,mixing in water forming a transparent precursor liquid.The effects of the microwave out-put power （200,400,600,and 700 W）on the microstructure,morphology and specific surface area of MgAl2O4 powders were analyzed.The results show that the microwave-assisted combustion method can accelerate combusti on reacti on to produce l arge vol umes of gas i nstantl y,formi ng ul tra-fi ne MgAl 2 O4 parti cl es.Moreo-ver,the increasing microwave output power accelerates the oxidation of urea,which is beneficial to the growth of MgAl2O4 grains.Under the conditions of microwave power 700 W for 2 min,the high crystallinity MgAl 2 O4 powder wi th a uni form parti cl e si ze di stri buti on （average grai n si ze of 56.03 nm）can be prepared.