摘要
通过溶胶 凝胶法将NiFe2O4纳米颗粒分散于SiO2基体中,制得NiFe2O4/SiO2纳米复合体。利用XRD,DSC,TEM和VSM对合成的(NiFe2O4)wSiO2(1-w)(5%≤w≤55%)纳米复合体进行了表征。研究结果显示:w<15%的纳米复合体均以非晶态存在,在15%≤w≤50%的范围内,随着w的增加,NiFe2O4的晶粒尺寸从2nm增长到25nm,w进一步增加则会导致材料中NiFe2O4晶粒尺寸减小。所制备的NiFe2O4/SiO2纳米复合体的饱和磁场强度随晶粒尺寸增加而增加,变化范围为3.7～11.0A·m2·kg-1;矫顽力值最大可以达到2.49×104A·m-1,是纯NiFe2O4大块材料矫顽力值的4倍以上。
Nanocomposites with nickel ferrite nanoparticles uniformly dispersed in silica matrix were successfully synthesized by sol-gel process. The obtained (NiFe_2O_4)_wSiO_(2(1-w))(5%≤w≤55%) samples were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscope (TEM) and vibration sample magnetometer (VSM). The results show that as w≤15%, the materials have an amorphous character, at the range of 15%≤w≤50%, the crystalline sizes increase ranging from 2nm to 25nm with increasing w, while at higher concentrations, a decrease in the crystalline sizes is observed. M_s increases with the crystalline size, ranging in 3.711.0 A·m^2·kg^(-1) and coercivity can be as high as 2.49×10~4 A·m^(-1), which is more than four times higher than the coercivity of bulk nickel ferrite.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2004年第11期1901-1905,共5页
The Chinese Journal of Nonferrous Metals
