Research on structure and performances of self-reactive spray formed multiphased ceramic preforms in different systems

Based on the main system of Ti-B₄C-C (sucrouse as the precursor of carbon) in mole ratio and with the additives of 5wt%Al, 5wt%Al＋20wt%Al-Ni and 5wt%Al＋20wt%Cu-Ni, the Ti(C,N)-TiB₂ multi-phased ceramic preforms were prepared by self-reactive spray forming technology. And the structure and mechanical performances of the self-reactive spray formed preforms in different systems were contrastively studied. The results show that the four kinds of preforms have the similar structural character, which is composed of the main phases of continuous matrix phase Ti(C_x, N_y), dispersed micro/nanometric rodlike grains TiB₂, some by-product phases and a few of pores. The preforms of Ti-B₄C-C-Al system have the highest hardness. The preforms of Ti-B₄C-C-Al ＋Cu-Ni system have the lowest density and flexural strength. The preforms of Ti-B₄C-C-Al ＋Al-Ni system have the highest density, flexural and fracture toughness, which is due to the crack deflection and pinning and micro-cracks toughening mechanism.