Ternary compounds and phase equilibria in Ti-Ge-C and Ti-Ge-B

Bulk samples of nearly single-phase Ti2GeC and Ti3CeC2 were fabricated using a synthesis process similar to one developed to produce bulk Ti3SiC2. Elemental powders were stored and mixed under argon and 2 g pellets were uniaxially pressed and encapsulated in quartz under vacuum for annealing. Additional samples were synthesized to establish the isothermal section of the ternary Ti-Ge-C phase diagram at 1200 degrees C. The only ternary compounds present were Ti3GeC2 and Ti2GeC, and the equilibria between these and other phases in the system were established for the first time. Attempts at substituting boron for carbon in Ti3GeC2 and Ti2GeC by the same technique proved unsuccessful. The phase distributions in Ti-Ge-B samples at 1200 degrees C were consistent with a previously established ternary diagram at 700 degrees C which indicated that no ternary phases of this or any other type are present at equilibrium in the Ti-Ge-B system.