稀土Gd^3+掺杂对钴铁氧体结构与吸波性能的影响

Structure and Microwave Absorption Properties of Rare Earth Gd Doped Cobalt Ferrite

以十六烷基三甲基溴化铵(CTAB)为表面活性剂,C4H6CoO4·6H2O和FeCl3·6H2O为原料,晶化温度180℃,晶化时间8 h,在pH=11的条件下采用水热法制备钴铁氧体纳米颗粒。探究了稀土元素Gd^3+的掺杂量对纳米钴铁氧体微观结构与吸波性能的影响。利用X射线衍射(XRD)仪、红外光谱(FT-IR)、透射电镜(TEM)和矢量网络分析(VNA)仪对制备的复合钴铁氧体结构性能进行表征。结果表明,稀土元素Gd^3+会对钴铁氧体的晶粒尺寸、形貌和吸波性能产生较大影响。当稀土元素Gd^3+掺杂量x≤0.025时,复合钴铁氧体晶粒尺寸随着掺杂量增加在逐渐减小,晶格常数逐渐增加,颗粒的形状变为不规则四边形。当稀土元素Gd^3+掺杂量x>0.025时,由于稀土元素Gd^3+在钴铁氧体中固溶度达到限值,会产生Gd(OH)3杂质,使钴铁氧体晶粒尺寸变大。当稀土元素Gd^3+的掺杂量x=0.025时,所制备的钴铁氧体介电损耗与磁滞损耗增强,吸波反射率达到最小,为-14.9 dB。

When the cetyltrimethylammonium bromide(CTAB)was used as surfactant,C4H6CoO4·6H2 O and FeCl3·6H2 O as starting material,the crystallization temperature was 180℃,the crystallization time lasted 8 h,and the pH was 11,cobalt ferrite nanoparticles were prepared by a hydrothermal method.The doped rare earth element Gd^3+was used to control the structure and absorbing properties of cobalt ferrite,and at the same time we explored the impact of rare earth element amount on the microstructure and microwave absorbing properties of nano cobalt ferrite.The structure and absorbing properties of cobalt ferrite were characterized by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),transmission electron microscopy(TEM)and vector network analyzer(VNA).It is found that during the period of the preparation of cobalt ferrite,the doping of rare earth element Gd^3+has a great influence on grain size,morphology and absorbing properties.The results show that when the doping amount of Gd^3+x≤0.025,the grain size of cobalt ferrite becomes smaller,while the lattice constant gradually increases and the shape of the particles becomes irregular quadrangles with the increase of doping amount,which indicates that rare earth element Gd^3+can make the particles smaller.When the solid solubility of the Gd^3+in the cobalt ferrite reaches the limit,Gd(OH)3 impurity is generated,and the cobalt ferrite grain size is increased when the Gd^3+doping amount x>0.025.The absorbing reflectivity of cobalt ferrite reaches the minimum values of–14.9 dB when the doping amount of Gd^3+is 0.025.