| 摘要 |
A transition metal carbide (for example, WC) is prepared by the following steps. A carbon-precursor mixture is formed by mixing a precursor comprised of (i) a transition metal oxide (for example, WOx) and (ii) a material selected from the group consisting of: a transition metal (for example, W); a transition metal carbide (for example, WC) and a substoichiometric carbide (W2C), in the presence of a source of carbon (for example, carbon black) in an amount sufficient to form a reduced mixture comprised of the transition metal carbide and substoichiometric transition metal carbide, wherein the amount of the transition metal oxide and transition metal is essentially zero in said reduced mixture. The carbon-precursor mixture is heated in a reducing atmosphere (for example, 5 percent hydrogen in argon) to a reducing temperature and for a time sufficient to produce the reduced mixture. The reduced mixture is milled in the presence of a source of carbon in an amount sufficient to carburize the substoichiometric transition metal carbide to form the transition metal upon heating in a reducing atmosphere. Finally, the milled reduced mixture is heated in a reducing atmosphere to a carburizing temperature that is greater than the reducing temperature for a time sufficient to carburize the substoichiometric transition metal carbide to form the transition metal carbide of this invention (for example, WC). |
