Reaction path of the synthesis of TiC-TiB2 in Cu-Ti-B4C system

The reaction path of TiC-TiB2 formation in 20 wt.% Cu Ti-B4C powder mixtures was studied by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Cu-Ti intermetallics (mainly Ti2Cu and TiCu) were formed initially via solid-state diffusion reactions between Cu and Ti particles; and then the Cu-Ti liquids were formed from the eutectic reaction between Ti2Cu and TiCu at about 965 degrees C and the melting of the Ti2Cu, Cu-Ti liquid spread over the B4C and Ti particles, subsequently carbon and boron atoms from the bulk B4C continuously diffuse into the liquid phase to form liquid Cu-Ti-B-C. Finally, TiC and TiB2 particulates precipitate out of the saturated liquid. The exthermic reaction was complete after the addition of Cu. The results showed that Cu not only participated in the reaction, but changed the reaction path between Ti and B4C.