The synthesis of YBa₂Cu₃O_7-x (YBCO or 123) superconductor was carried out under hyper- and hypo-eutectic conditions with different ammonium compounds, i.e., ammonium nitrate, formate, acetate, carbonate, bicarbonate, and tetramethylammonium nitrate. The aim was to find more affordable synthetic pathways using highly available and cheaper compounds, as well as to study the crystal formation under no-carbon conditions when ammonium nitrate was employed. Best results were obtained when eutectic conditions were achieved, namely by ammonium nitrate and YBaCu nitrates in a 5:1 molar ratio (81% of the superconductor). Ammonium formate, acetate, carbonate, and bicarbonate did not produce eutectic mixes. Temperature analysis of the reaction carried out by ammonium nitrate/YBaCu nitrates indicated the formation of barium carbonate, despite no carbon source being used in this reaction. This phenomenon is further discussed in this work. Consequently, tetramethylammonium nitrate, as a chelator and carbon source, was used, providing >96% of the superconductor.

中文翻译：

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形成溶剂化共晶混合物的金属氧化物的合成及其在超共晶和次共晶条件下的合成性能研究

YBa ₂ Cu ₃ O _7-x的合成（YBCO或123）超导体是在过共晶和过共晶条件下用不同的铵化合物（即硝酸铵，甲酸盐，乙酸盐，碳酸盐，碳酸氢盐和硝酸四甲基铵）制成的。目的是寻找使用高价位和廉价化合物的更廉价的合成途径，并研究使用硝酸铵在无碳条件下的晶体形成。当达到共晶条件时，即通过摩尔比为5：1的硝酸铵和YBaCu硝酸盐（超导体的81％）可获得最佳结果。甲酸铵，乙酸盐，碳酸盐和碳酸氢盐不会产生低共熔混合物。尽管在该反应中没有使用碳源，但通过硝酸铵/ YBaCu硝酸盐对反应进行的温度分析表明形成了碳酸钡。在这项工作中将进一步讨论这种现象。因此，使用硝酸四甲基铵作为螯合剂和碳源，提供了> 96％的超导体。