合金Co-Zr-B纳米粉末的相组成及磁性能研究

将硼氢化钠(NaBH4)的水溶液加入到氯化钴(CoCl2·6H2O)和硫酸锆(Zr(SO4)2·4H2O)的混合水溶液中,利用BH-4把混合溶液中的CO2 和Zr4 同时还原出来,首次成功制备出非晶态Co-Zr-B三元纳米合金粉末.用电感耦合等离子体发射光谱(ICP)、X射线衍射(XRD)、选区电子衍射(SAED)、透射电子显微镜(TEM)、差示扫描量热法(DSC)以及振动样品磁强计(VSM)分析了样品的成分、结构和磁性能.发现所制备的不同成分的粉末颗粒呈球形,粒径在20～60nm之间.纳米粉末由非晶相基体和少量晶体相杂质组成,而非晶相基体又由Zr基非晶颗粒和含有Zr的Co基非晶颗粒构成.还原产物中的Co原子和Zr原子的分数之比与金属盐混合溶液中的Co2 与Zr4 离子的分数之比几乎相等.提高NaBH4溶液的加入速度,可增加产物中B元素的含量.样品的晶化温度在765.1～771.3K之间,样品的热稳定性随Zr含量的增加而增加,样品的磁性能也与样品中Co、Zr原子的含量之比有关.当原子数x(Co)/x(Zr)比值从1.94增加到5.14时,饱和磁化强度从4.76emu/g增加到8.87emu/g,矫顽力在1271.66A/m(15.98Oe)到2133.49A/m(26.81Oe)之间不规则变化.

STUDY OF PHASE COMPONENTS AND MAGNETIC PROPERTIES OF AMORPHOUS Co-Zr-B ALLOY NANO-POWDERS

The magnetic Co-Zr-B amorphous alloy powders of nearly spherical morphology 20-60nm in size were obtained first time by the reduction of an aqueous solution of zirconium sulphate and cobalt chloride added with an aqueous solution of sodium borohydride.XRD,SAED and DSC studies showed that the product is partially amorphous with small volume fraction of crystalline phases,and the main amorphous phase consists of Zr-based amorphous particles and the Co-based Zr-containing amorphous particles.It was found that the Co/Zr ratio of powders is equal to Co2+/Zr4+ ratio in original mixed solution and the boron content is increased with the addition rate of NaBH4 solution.The crystallization temperature of powder is in the range of 765.1-771.3K.The thermal stability of amorphous Co-Zr-B powder is increased with increasing of zirconium content.When the Co/Zr ratio in the samples is increased from 1.94 to 5.14,the saturation magnetization is increased monotonously from 4.76 emu/g to 8.87 emu/g,but the coercivity is changed irregularly from 1271.66A/m to 2133.49A/m(15.98Oe to 26.81Oe).