Study of the interactions between HfB2 and Hi-Nicalon™ fiber

This work aims at studying the interactions between Hi-Nicalon SiC fiber and HfB2 in presence of various sintering additive, such as Si3N4 or ZrSi2. Spark plasma sintering was used as suitable technique to interrupt the sintering at intermediate temperatures and thus analyze the microstructure evolution at the various densification stages. SEM investigations enabled to disclose the interaction mechanisms not only among fiber and matrix, but also revealed the curious mechanisms of formation of core-shell structures in HfB2 grains when ZrSi2 was employed.