Synthesis of transition metal carbonitrides
AssigneeThe Regents of the University of California
InventorsZuhair A. R. Munir, Maryam Eslamloo-Grami
Life of this patent
Estimating the term…
Abstract
Transition metal carbonitrides (in particular, titanium carbonitride, TiC.sub.0.5 N.sub.0.5) are synthesized by a self-propagating reaction between the metal (e.g., titanium) and carbon in a nitrogen atmosphere. Complete conversion to the carbonitride phase is achieved with the addition of TiN as diluent and with a nitrogen pressure .gtoreq.0.6 MPa. Thermodynamic phase-stability calculations and experimental characterizations of quenched samples provided revealed that the mechanism of formation of the carbonitride is a two-step process. The first step involves the formation of the nonstoichiometric carbide, TiC.sub.0.5, and is followed by the formation of the product by the incorporation of nitrogen in the defect-structure carbide.
Claims6
A method for preparing a single-phase transition metal carbonitride, comprising:
- forming a mixture of at least one transition metal powder and a transition metal nitride as an additional source of transition metal with elemental carbon in an atomic ratio of metal:carbon corresponding to that in said transition metal carbonitride;
- pressing the powder mixture to form a compressed green body;
- and
- initiating a self-propagating wave reaction in said green body by imparting energy to said green body at an end thereof under an atmosphere of essentially pure nitrogen at a pressure in the range of about 0.1 to about 1.4 Mpa.
Dependencies are inferred from the claim text.