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采用X射线衍射仪和扫描电镜系统研究了纯MgB2和碳掺杂MgB2超导块材在的盐酸溶液中(pH=2)酸浸后的相成分和微观结构演变过程。XRD结果显示,纯MgB2和碳掺杂MgB2超导块材均迅速与盐酸反应而分解。分解反应在5h后完全结束,主要的固态产物是B(OH)3和MgCl2(6H2O)。SEM结果显示,纯MgB2和碳掺杂MgB2超导块材与酸反应都是从晶界处开始,与纯MgB2块材相比,碳掺杂MgB2块材在与酸反应后仍保持致密的结构特征。而对酸浸10min后纯MgB2和碳掺杂MgB2块材的临界超导转变温度测定结果显示,碳掺杂MgB2块材的临界超导转变温度保持不变,说明碳掺杂可提高MgB2在酸中的稳定性。
The phase composition and microstructure evolution of pure MgB2 and carbon-doped MgB2 superconducting blocks in hydrochloric acid solution (pH = 2) after acid leaching were investigated by X-ray diffraction and scanning electron microscopy. XRD results show that both pure MgB2 and carbon-doped MgB2 superconducting blocks rapidly react with hydrochloric acid to decompose. The decomposition reaction ended completely after 5 h. The main solid products were B (OH) 3 and MgCl2 (6H2O). The SEM results show that both pure MgB2 and carbon-doped MgB2 superconducting blocks react with the acid starting from the grain boundaries. Compared with pure MgB2 blocks, the carbon-doped MgB2 blocks remain dense after reacting with acid feature. The critical superconducting transition temperature of pure MgB2 and carbon-doped MgB2 block after acid leaching for 10min shows that the critical superconducting transition temperature of carbon-doped MgB2 block remains unchanged, indicating that carbon doping can increase the MgB2 in acid In the stability.