Preparation of superconducting Bi-Sr-Ca-Cu-O ceramics by the sol-gel method
Preparation of superconducting Bi-Sr-Ca-Cu-O ceramics by the sol-gel method
复制标题
溶胶-凝胶法制备超导Bi-Sr-Ca-Cu-O陶瓷
DOI：
10.1007/bf01129938
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发表时间：
1990
影响因子：
4.5
通讯作者：
S. Sakka
中科院分区：
文献类型：
--
作者：
H. Zhuang;H. Kozuka;S. Sakka
以含有乙酸和酒石酸的金属乙酸盐水溶液为原料，通过溶胶-凝胶法制备了超导Bi-(Pb)-Sr-Ca-Cu-O陶瓷。采用热分析、红外吸收光谱和X射线衍射技术研究了凝胶的凝胶化和向Bi2Sr2CaCu2Ox相的转化条件。结果发现，C4H6O6/Cu摩尔比约为0.4的酒石酸溶液可得到透明凝胶。假定凝胶基质由羧酸根阴离子和金属阳离子组成。摩尔组成为Bi∶Sr∶Ca∶Cu=2∶2∶2∶3的凝胶在270～600℃低温下分解为CaCO3、CaO、CuO和Bi1-xSrxOy(x=0.2～0.3)，并在800℃时通过复杂的中间态生成Bi2Sr2CaCu2Ox相。加热产物快速冷却提高了摩尔组成Bi∶Sr∶Ca∶Cu=2∶2∶2∶3的凝胶的Tc(end)，而缓慢冷却则提高了摩尔组成Bi∶Pb∶Sr∶Ca∶Cu=1.85∶0.35∶1.9∶2.0∶3.1的含铅凝胶的Tc(end)。后者显示 Tc（开始）为 115 K，Tc（结束）为 105 K。
Superconducting Bi-(Pb)-Sr-Ca-Cu-O ceramics were prepared through the sol-gel method using an aqueous solution of metal acetates containing acetic acid and tartaric acid. The conditions of gelation and conversion of gel to Bi2Sr2CaCu2Oxphase were studied by thermal analysis, infrared absorption spectroscopy and X-ray diffraction technique. It was found that transparent gels were obtained from the solutions containing tartaric acid, with a molar ratio of C4H6O6/Cu of about 0.4. The gel matrix was assumed to be composed of carboxylate anions and metal cations. A gel of molar composition Bi∶Sr∶Ca∶Cu = 2∶2∶2∶3 was decomposed to CaCO3, CaO, CuO and Bi1-xSrxOy(x = 0.2 to 0.3) at low temperatures of 270 to 600 ° C and produced Bi2Sr2CaCu2Oxphase at 800 ° C via complex intermediate states. A rapid cooling of the heated product increasedTc(end) in the gel of molar composition Bi∶Sr∶Ca∶Cu = 2∶2∶2∶3, while a slow cooling increasedTc(end) in the lead-containing gel of molar composition Bi∶Pb∶Sr∶Ca∶Cu = 1.85∶0.35∶1.9∶2.0∶3.1. The latter showedTc(onset) at 115 K andTc(end) at 105K.
DOI：
10.1007/bf01303701
发表时间：
1986-01-01
期刊：
ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER
影响因子：
--
作者：
BEDNORZ, JG;MULLER, KA
通讯作者：
MULLER, KA