燃料及燃料/氧化剂比对ZnCr_2O_4的影响

Effect of Fuel Type and Fuel-to-Oxidant Ratio on Synthesis of ZnCr_2O_4

采用溶液燃烧法一步快速合成尖晶石型纳米ZnCr2O4,用X射线衍射仪和扫描电镜系统研究了不同燃料、燃料/氧化剂比对ZnCr2O4晶相组成,晶粒大小和微观形貌的影响。结果表明:燃料种类和燃料/氧化剂比对合成产物晶相组成,晶粒大小和微观形貌有显著影响。适宜的燃料/氧化剂比随燃料的不同而变化,甘氨酸为燃料,燃料/氧化剂比在富燃(+50%)可得到8.1nm纯相结构致密的ZnCr2O4纳米晶体;尿素为燃料,在化学计量比得到晶型良好块状多孔晶粒大小为10.2nm纳米晶体;乙醇胺为燃料,在化学计量比得到致密团聚晶粒大小为12.7nm的纳米晶体。

The spinel type compound ZnCr2O4 nanopowders were prepared rapidly by one step solution combustion method.The effect of fuel and fuel-to-oxidant ratio on the phase composition,grain size and morphology of the as-synthesized products was systematically studied by X-ray diffraction（XRD） and scanning electron microscope（SEM）.The results showed that fuel and fuel-to-oxidant ratio played an important role in phase composition,grain size and morphology.The suitable fuel-to-oxidant ratio varied with fuel type.When glycine was used as fuel,a pure phase dense structure ZnCr2O4 with a crystallite size of 8.1nm was obtained in the fuel-rich（＋50%） ratio.whereas for urea,ZnCr2O4 with lump-like porous morphology was prepared in the condition of stoichiometric with a crystallite size of 10.2nm.While dense reunion ZnCr2O4 powders with a crystallite size of 12.7nm were obtained by ethanolamine also in stoichiometric condition.