馬 麟， 李亞明， 張子立， 周美玲
(北京工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院
國(guó)家教育部功能材料重點(diǎn)實(shí)驗(yàn)室， 北京 100022)
摘 要: 采用非原位粉末套管法制備MgB2/Fe單芯超導(dǎo)帶，并通過X射線衍射擬合分析、 差熱分析對(duì)退火前后的MgB2/Fe帶超導(dǎo)芯進(jìn)行了相成分及不均勻性研究。結(jié)果表明： 所有的超導(dǎo)芯中均含有一定量的MgO， 在高溫退火樣品中靠近鐵套管處MgO含量最多； 在MgB2超導(dǎo)芯內(nèi)部檢測(cè)到少量的MgB4， 這是由MgB2分解所得；在MgB2/Fe之間的界面處存在反應(yīng)層Fe2B，該相是由Fe23B6分解所得到的。 MgB2超導(dǎo)芯與鐵套管之間的反應(yīng)以及超導(dǎo)芯中氧的存在限制了這種非原位法制備的MgB2/Fe帶中超導(dǎo)相的含量、 純度和均勻性。
關(guān)鍵字: 非原位MgB2/Fe超導(dǎo)帶； X射線衍射擬合分析； 差熱分析； 相成分分析
ex-situ PIT MgB2/Fe monofilamentary tapes
ZHAO Yue，MA Lin，LI Ya-ming，ZHANG Zhi-li，ZHOU Mei-ling
（The Key Laboratory of Advanced Functional Materials,
Ministry of Education Department of Materials Science and Engineering,
Beijing University of Technology, Beijing 100022, China）
Abstract: The monofilamentary MgB2/Fe superconducting tapes were fabricated by an ex-situ PIT method. The quantitative phase analysis was carried out using X-ray diffraction and differential thermal analysis on short samples heattreated at 700, 850 and 920 ℃ in vacuum, respectively. The reaction mechanism of MgB2 core during the process of the heat treatment was discussed. The impurity phase of MgO was found in all MgB2 cores and the largest amount was detected near the Fe sheath of the sample annealed at the highest temperature. MgB4 appeares in the inner part of MgB2 core, which is possibly formed by the decomposition of MgB2. A reaction layer (Fe2B) is observed between MgB2 core and Fe sheath, which is decomposed by Fe23B6. The result indicates that the presence of the oxygen inside sheath material is the main obstacle to the further improvement of the phase purity and homogeneity of the ex-situ PIT MgB2/Fe tapes.
Key words: ex-situ MgB2/Fe superconducting tape; X-ray diffraction refinement; differential thermal analysis; phase composition analysis
