適用於普通化學實驗之材料化學實驗－利用檸檬酸鹽凝膠法製備釔鋇銅氧高溫超導體

A General Chemistry Laboratory Related to Materials Chemistry-Synthesis of Y-Ba-Cu-O High-Temperature Superconductor by Citrate Gel

佘瑞琳(Jui-Lin She) ； 劉如熹(Ru-Shi Liu)

《化學》 59卷4期 (2001/12) Pp. 509-517

https://doi.org/10.6623/chem.2001059

摘要

本研究乃設計以檸檬酸鹽凝膠法製備高溫超導體之普通化學實驗教材，使學生同時學習以固態反應法及檸檬酸鹽凝膠法合成釔鋇銅氧（YBa_2Cu_3O_(7-x)，x ≤ 0.25）高溫超導體，並比較其製程與產物之差異性，實驗所用原料為釔、鋇、銅之硝酸鹽，依化學計量比稱取後加水及加熱溶解，再加入與總金屬等克當量數的檸檬酸，並滴加乙二胺調整溶液之pH值為6，以形成穩定錯合物。溶液經水浴法蒸發濃縮後，製得之深藍紫色檸檬酸鹽凝膠，首先在300°C空氣中加熱2小時，使乙二胺/檸檬酸鹽錯合物得以裂解，然後再於空氣中以930°C之高溫分別鍛燒及燒結各20小時，製得在液氮溫度下具超導性且為單一相之釔鋇銅氧高溫超導體，本實驗教材經試作完成後，於台灣大學之暑修實驗中進行小規模試做，成效良好。

關鍵字

高溫超導體製備 ； 普通化學實驗 ； 材料化學 ； 檸檬酸鹽凝膠法

並列摘要

There are three methods generally used to prepare superconductors. Those are solid state reaction, citrate gel and coprecipitation. In this study, an experiment entitled ＂Y-Ba-Cu-O High-Temperature Superconductor Synthesized by Citrate Gel＂ is designed for General Chemistry Laboratory in order to compare the differences between the Y-Ba-Cu-O superconductor synthesized by solid -state react ion and by citrate gel. In this experiment, Y(N0_3)_3•6H_2O, Ba(NO_3)_2, Cu(NO_3)_2•3H_2O, citric acid, and ethylenediamine are used as starting materials to form a citrate gel. After heating at 300°C for 2 h to pyrolyze the citrate gel, the product obtained is processed as that of solid state method. Y-Ba-Cu-O high-T_c superconductors prepared by solid state reaction and citrate gel are obtained as determined via X-ray powder diffract ion. Both of them show diamagnetism at liquid nitrogen temperature. Although the cost of the superconductor prepared by citrate gel is higher than that of solid state reaction, and the processes are more complicated, more techniques, such as preparation of sol-gel, and operation of pH-meter, can be practiced in the citrate gel method.

並列關鍵字

general chemistry laboratory ； high-T ； superconductor ； materials chemistry ； citrate gel