312 PROCESS FOR FORMING 312 PHASE MATERIALS AND PROCESS FOR SINTERING THE SAME

摘要

(a) one selected from the group consisting of (i) at least one transition metal species, (ii) at least one minor species selected from the group consisting of aluminum species, germanium species and silicon species, and (iii) boron species, carbon species and nitrogen species Providing a mixture of at least two non-metallic species; And (b) heating the mixture to a temperature of from about 1000 ° C to about 1800 ° C for a time sufficient to form the M ₃ X ₁ Z ₂ phase in the atmosphere within the substantially sealed heating zone, A method of forming a material comprising an M ₃ X ₁ Z ₂ phase, comprising the step of: providing an O ₂ partial pressure of less than ^-6 atm. This method provides a substantially monolithic material comprising very few MZ _x phases. Providing a high purity M ₃ X ₁ Z _two phase powder preform; And firing the preform at a temperature of from about 1000 ° C to about 1800 ° C for a time sufficient to form a dense substantially single-phase M ₃ X ₁ Z _two- phase workpiece in an atmosphere in a substantially enclosed heating zone, that there is provided a process for preparing a substantially single phase of about 1 M ₃ X ₁ Z ₂ a workpiece, dense, comprising characterized by having an O ₂ partial pressure of less × 10 ^-6 atm.