Wetting and pressureless infiltration in the CuTi/Al2O3 system under poor vacuum

Work is aimed at preparation of Cu/Al2O3 composite by pressureless metal infiltration of porous alumina with simple vacuum equipment. Improvement of wetting by addition of Ti to Cu is investigated in sessile drop tests with various geometrical configurations in vacuum of 1-10 Pa. The results showed that a pre-alloyed Cu did not wet alumina substrate while stacked Cu and Ti blocks did, even though the latter had the same nominal alloy content (Ti: 10 wt%). This result had been proved by a following pressureless infiltration test, i.e. a CuTi/Al2O3 composite was formed with stacked Cu and Ti blocks at 1300 °C. Wettability, interfacial chemistry and microstructure were discussed with the aid of SEM and EDAX analysis in the paper. It was suggested that the initial reactant, which benefits the wettability, could be evolved to the one with a higher O:Ti ratio due to poor vacuum condition, higher temperature and longer holding time.