Preparation of Molybdenum Carbide with WC-Type Structure

Abstract

Since the discovery of the complete series of solid solutions (Mo_1−x W_x)C (X= 0 to 1) hexagonal molybdenum carbide with WC-type structure is considered an interesting material for WC-substitution in several applications. With the preparation techniques used and proposed so far no single phase MoC (Mo₂C free) can be obtained. Thus a method to favor the formation of hex. MoC over the other molybdenum monocarbides was developed by using additives of metal powders to the binary alloy. To reach thermodynamic equilibrium at the low temperatures at which the MoC with WC-type structure is stable (below 1190°C) an auxiliary bath method is employed. To separate the carbide from the bath metal an electrochemical technique is used rather than an acidic-mixture in order to avoid chemical side reactions. The final product is a dark grey, well crystallized MoC-powder with WC-type structure.