Issue
HWAHAK KONGHAK,
Vol.37, No.6, 930-936, 1999
발화합성법에 의한 YBCO계 고온 초전도체 제조 및 특성
Preparation and Characterization of YBCO High-Tc Superconductor Manufactured by Pyrophoric Synthetic Method
YBa2Cu3O7-x계 고온 초전도체를 원료물질인 Y2O3, BaCO3, CuO 및 AgNO3 분말로부터 발화합성법으로 제조하였다. YBa2Cu3O7-x(Y123)와 1몰의 Y123에 Ag를 0.1 몰, 0.2몰 및 0.3몰 첨가한 YBa2Cu3O7-x(Y123-Agy)의 특성을 입도분석기, differential scanning calorimeter(DSC), themogrvimetric analysis(TGA), X-ray diffractometer(XRD), 4단자 저항측정장치(4-probe resistivity measuring equipment), scanning electron microcope(SEM) 및 electron prove microanalysis(EPMA) 등으로 분석하였다. 50℃에서 건조한 발화용액은 210-240℃사이에서 발열반응이 일어나면서, 급격한 무게감소를 보여주는데, 240℃에서의 무게감소는 75%였다. 발화된 분말은 810℃와 975℃사이에서 흡열반응과 함께 무게감소가 있었으며, YBa2Cu3O7-x가 형성되는 것을 확인하였다. 880℃에서 24시간 소결한 YBa2Cu3O7-x의 Tc,zero는 92.2K였고, Y123에 Ag를 0.2 몰 첨가한 경우에 입자가 치밀한 미세구조를 갖는 것을 알 수 있었다.
The YBaCu3O7-x high-temperature superconductors were prepared by pyrohporic synthetic method from Y2O3, BaCO3, CuO and AgNO3 powders. The superconducting properties of YBaCu3O7-x and YBaCu3Ag(sub>yO7-x added to Ag of 0.1 mol, 0.2 mol, and 0.3 mol were investigated with particle size analyzer, differential scanning calorimeter(DSC), thermogravimetric analysis(TGA), X-ray diffractometer(XRD), 4-probe resistivity measuring equipment, scanning electron microcope(SEM), and electron prove micoranalysis(EPMA). The weight loss of 75% is observed in the temperature range of 210℃ to 240℃, which occurs with an exothermic peak of the powder neutralized and dried at 50℃. The powder prepared by pyrophoric synthetic method occurs with an endothermic peak and the weight loss in the temperature range of 810℃ to 975℃, and the simultaneous fomation of the YBaCu3O7-x. The Tc,zero of YBaCu3O7-x sintered at 880℃ for 24 hr was 99.2K, and microstructure of YBaCu3O7-x-Ag0.2 was enhanced.
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