CaCl2熔盐中自烧结电解制备粉体Cr3C2及其机制

Preparation and Reaction Mechanism of Cr3C2 by Electrochemical Reduction of the Cathode Self-Sintered in Molten CaCl2 Salt

摘要:

以氧化铬和石墨粉为原料，采用聚乙烯醇粘接，压制成阴极片，以光谱石墨棒为阳极，在800 ℃氯化钙熔盐中，恒电压3.2 V下，阴极片自烧结电解制备碳化铬。采用XRD、SEM和EDX对样品进行表征。结果表明：粘接的阴极片满足熔盐电解的强度要求，通过熔盐电解过程的自烧结阴极片有效地粘接在一起，并制备出具有良好烧结性能、组分单一的Cr3C2粉体。该法制备Cr3C2的电流效率不低于37.3%。采用恒电位电解法和循环伏安法对电解机制的研究表明，熔盐电解制备Cr3C2的反应机制为：Cr2O3 + e- →Cr+ O2-, Cr+C→Cr3C2两步完成

Abstract:

The Cr2O3 and C powder with polyvinyl alcohol were mixed and pressed to form the pellets. The pellets of the Cr2O3-C mixtures were self-sintered and directly electrochemically reduced to Cr3C2 at the same time in molten CaCl2 at 800 oC and 3.2 V with a graphite anode. The samples were characterized by XRD, SEM, and EDX. The results show that the Cr2O3-C mixtures satisfy the bond strength requirement when electrolyzing. High purity Cr3C2 powder with the excellent sintering nature is obtained. The current efficiency is no less than 37.3%. The results of the cyclic voltammetry measurement and the potentiostatic electrolysis reveal that the reaction mechanism of Cr3C2 formation by the directly electrochemical reduction is two steps: Cr2O3+e-→Cr + O2 and Cr+C→Cr3C2.