REACTIONS OF TI AND ZR WITH ALN AND AL2O3

We studied the reactions of Ti and Zr with AlN, 99.8% Al2O3 and 95% Al2O3. The substrates were chosen to represent a simple nitride (AlN), a simple oxide (99.8% Al2O3), and a simple oxide with a silicate grain boundary phase (95% Al2O3). The activities of the Ti and the Zr were varied by dissolving them at 1 and 5 wt% in the 72 Ag-28 Cu eutectic composition, which is otherwise unreactive with the ceramics. Reactions were studied by measuring the variation of the alloy contact angle on the ceramic with time at temperature and by determining the compositions of interfacial reaction products. Contact angles were lower for Ti alloys than for those containing Zr. Reaction products were primarily the nitrides of Zr and Ti for reaction with AlN and the respective oxides for reaction with Al2O3. Complex alloy phases were found in the metal away from the ceramic-metal reaction zone,