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研究在900°C的CaCl_2-Na Cl熔融盐体系中,以SnO_2、Nb_2O_5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。SnO_2在烧结过程中被碳还原为金属Sn,Nb_2O_5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Nb_3Sn。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。
In the molten salt system of CaCl_2-NaCl at 900 ° C, SnO_2, Nb_2O_5 and carbon powder were used as precursors, and the NbC-Sn composite powders were successfully prepared by electrochemical reduction and in-situ carbonization. By analyzing the products of different reaction stages, the reaction mechanism was studied. The influence of the amount of carbon powder in the precursor on the final product was investigated. NbC was prepared by acid leaching of NbC-Sn powder. The results show that NbC and Sn particles with size of 50 ~ 100 nm and 200 nm are prepared by this method, and the two are tightly packed together. During the sintering process, SnO_2 is reduced to metal Sn by carbon, and gradually reduced to Nb in the molten salt, which reacts with carbon to form NbC. Among them, after the niobate formation and decomposition, the formation of low-cost niobium oxide and further reduction process. When the cathode sheet of carbon is not enough, it will lead to incomplete reduction of niobium oxide and the formation of Nb_3Sn. The composite powder material is leached by aqueous HCl solution to obtain a well dispersed NbC powder material.