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

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.