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 Ti 3SiC2. Elemental powders were stored and mixed under argon and 2 g pel lets were uniaxially pressed and encapsulated in quartz under vacuum f or annealing. Additional samples were synthesized to establish the iso thermal 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 establish ed for the first time. Attempts at substituting boron for carbon in Ti 3GeC2 and Ti2GeC by the same technique proved unsuccessful. The phase distributions in Ti-Ge-B samples at 1200 degrees C were consistent wit h a previously established ternary diagram at 700 degrees C which indi cated that no ternary phases of this or any other type are present at equilibrium in the Ti-Ge-B system.