熔盐法制备Ba_(1-x)K_xBiO_3超导体及Ba_(0.6)K_(0.4)BiO_3的稳定性(英文)  

Preparation of Ba_(1-x)K_xBiO_3 by Molten Salt Method and Thermostability of Ba_(0.6)K_(0.4)BiO_3

作　　者：崔雅静[1] 陈永亮[1] 王法社[1] 李璟[1] 张勇[1] 赵勇[1] 

机构地区：[1]西南交通大学磁浮技术与磁浮列车教育部重点实验室,四川成都610031

出　　处：《稀有金属材料与工程》2009年第4期583-586,共4页Rare Metal Materials and Engineering

基　　金：2007 Innovation Fund for Ph.D.Student of Southwest Jiaotong University and China National Funds for Distinguished Young Scientists(50588201)

摘　　要：利用熔盐法在260°C的低温下制备出了单相Ba1-xKxBiO3(BKBO,0.315≤x≤0.6)样品。磁性测量结果表明,在x值整个范围内的BKBO样品都表现出超导电性,x=0.4时,超导转变温度达到最高值(Tc=30.6 K);粉末X射线衍射结果表明,所有样品中均含有少量的BaCO3杂相,它是由于反应过程中Ba(OH)2.8H2O和空气中的二氧化碳反应造成的;扫描电镜观察BKBO微观形貌为片状。为与熔盐法作比较,利用溶胶-凝胶法制备Ba0.6K0.4BiO3,发现此法难以制备出单相BKBO样品。利用热分析和退火处理来研究熔盐法制备Ba0.6K0.4BiO3的热稳定性,发现样品大约在400°C开始分解,表明Ba0.6K0.4BiO3在400°C以上是不稳定的。Ba1-xKxBiO3 （BKBO） samples with 0.315≤x≤ 0.6 were synthesized at a relatively low temperature of 260℃ by molten salt method. The superconductivity was tested in the whole range of x value, the highest superconducting transition temperature Tc= 30.6 K at x = 0.4. X-ray Diffraction patterns reveal that small amount of impurity phase of BaCO3 were detected in BKBO which is attributed to the reactions between Ba（OH）2-8H20 and CO2 in air. The plate-like morphology of BKBO was observed from SEM images. For comparison, sol-gel method was also used in synthesizing Ba1-xKxBiO3 sample, but no single phase of BKBO was obtained. For the sample of Ba1-xKxBiO3 prepared by molten salt method, the thermostability was investigated by thermogravimetrie analysis （TGA） and annealing treatment, and the sample was decomposed at 400 ℃ . The result showed that Ba1-xKxBiO3 was thermally unstable above 400℃.

关 键 词：Ba1-xKxBiO3 熔盐法 超导电性 

分 类 号：TM26[一般工业技术—材料科学与工程]