低温固相反应工艺对NiFe_2O_4纳米粉体形貌的影响

为了改善NiFe2O4纳米粉体气敏性,采用低温固相反应法制备了不同形貌的NiFe2O4纳米粉体.以FeSO4·7H2O、NiSO4·6H2O和NaOH作为反应物,充分研磨制备前驱体,通过先抽滤后600℃热处理和先600℃热处理后抽滤制备了两种NiFe2O4纳米粉体,通过X射线衍射和扫描电镜考察了不同制备工艺对纳米晶粒尺寸及形貌的影响.XRD和SEM分析结果表明:两种制备工艺均能生成NiFe2O4尖晶石相.先抽滤后热处理制备的NiFe2O4纳米粉体颗粒尺寸约为80nm,颗粒呈立方体结构.而先热处理后抽滤制备的NiFe2O4纳米粉体,由于热处理过程中存在Na2SO4相,使得NiFe2O4纳米粉体颗粒呈圆形片状结构分布,颗粒尺寸为50nm,厚度约10nm.

Effect of low-temperature solid-state reaction technique on morphology of NiFe2O4 nanopowder

In order to improve the gas sensitivity of NiFe2O4 nano-particles,NiFe2O4 nano-particles with different morphologies were perpared by low-temperature solid-state reaction technique. The precursor powder was prepared by rubbing FeSO4·7H2O,NiSO4·6H2O and NaOH sufficiently. Two kinds of NiFe2O4 nanoparticles were prepared by dealing with the precursor powder through pumping and filtrating first and then heat treating at 600 ℃,and heat treating at 600 ℃ first and then pumping and filtrating,respectively. Influences of the two preparation processes on particle size and morphology were investigated by XRD and SEM. Results show that the nano-powders prepared by the two methods are both with NiFe2O4 spinel phase. The particle size of NiFe2O4 spinel prepared by the first process is about 80 nm,and the particle morphology is cubic. While for the nanosize NiFe2O4 spinel particles prepared by the second process,the nanocrystal morphology is platelike,the particle size is about 50 nm,and the thickness is about 10 nm,because of the action of Na2SO4 phase during the heat treatment.