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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。
Single-phase Ba1-xKxBiO3 (BKBO, 0.315≤x≤0.6) samples were prepared by the molten salt method at a low temperature of 260 ° C. The magnetic measurements show that the BKBO samples show superconductivity over the entire range of x value and the superconducting transition temperature reaches the highest value (Tc = 30.6 K) at x = 0.4. The results of powder X-ray diffraction show that in all the samples Both contain a small amount of BaCO3 heterogeneous phase, which is caused by the reaction of Ba (OH) 2.8H2O and carbon dioxide in the air during the reaction. The microscopic morphology of BKBO is flaky by scanning electron microscopy. Compared with the molten salt method, Ba0.6K0.4BiO3 was prepared by sol-gel method, and it was found that it was difficult to prepare single-phase BKBO samples by this method. The thermal stability of Ba0.6K0.4BiO3 prepared by the molten salt method was studied by means of thermal analysis and annealing. It was found that the sample began to decompose at about 400 ° C, indicating that Ba0.6K0.4BiO3 was unstable above 400 ° C.