熔盐电化学合成NbC-Sn复合粉末

摘要

NbC-Sn composite powder was successfully prepared from SnO2, Nb2O5 and carbon by electrochemical reduction and carbonization in CaCl2-NaCl molten salt at 900 ℃. The reaction pathway was investigated by terminating electrochemical experiments for various durations. The influence of carbon on the final products was considered. NbC particles were obtained by leaching the composite with acid. The results showed that the aggregated NbC-Sn composite powdev contained NbC particles about 50-100 nm and Sn particles about 200 nm. SnO2 was reduced to Sn in the sintering process. Nb2O5 was electrochemically reduced to Nb in molten salt, experiencing some intermediate products of calcium niobates and niobium suboxides. Nb metal obtained was converted to NbC with assistance of carbon. The reduction of Nb oxides may be incomplete and Nb3Sn would be formed if carbon is insufficient in the cathodic pellet. NbC with good dispersity is produced by leaching NbC-Sn with HCl.%研究在900℃的CaCl2-NaCl熔融盐体系中,以SnO2、Nb2O5和碳粉为前驱体,使用电化学还原和原位碳化的方法,成功制备出NbC-Sn复合粉体材料.通过对不同反应阶段的产物进行分析,研究反应过程机理.考察前驱体中碳粉物质的量变化对最终产物的影响,并通过酸浸NbC-Sn粉体的方式制备NbC.研究表明通过该方法制备出尺寸分别为50~100 nm和200 nm的NbC和Sn颗粒,两者紧密地聚集在一起.SnO2在烧结过程中被碳还原为金属Sn,Nb2O5在熔盐中被逐步电化学还原为金属Nb,并与碳反应生成NbC.其中,历经了铌酸盐的形成与分解、低价铌氧化物的形成与进一步还原等过程.当阴极片中的碳不足时,会造成铌氧化物还原不完全并形成Nb3Sn.复合粉体材料通过HCl水溶液浸出,能够获得分散性很好的NbC粉体材料.