Titanium diboride (TiB2) was hot-pressed at a temperature of 1800 °C, and silicon nitride (Si3N4) was added as a sintering aid. The amount of Si3N4 that was added had a significant influence on the sinterability and mechanical properties of the TiB2. When a small amount (2.5 wt%) of Si3N4 was added, the Si3N4 reacted with titania (TiO2) that was present on the surface of the TiB2 powder to form titanium nitride (TIN), boron nitride (BN), and amorphous silica (SiO2). The elimination of TiO2 suppressed the grain growth effectively, which led to an improvement in the densification of TiB2. The formation of SiO2 also was deemed beneficial for densification. The mechanical properties - especially, the flexural strength - were enhanced remarkably through these improvements in the sinterability and microstructure. On the other hand, when a large amount (≥5 wt%) of Si3N4 was added, the mechanical properties were not improved much, presumably because of the extensive formation of a glassy Si-Ti-O-N phase at the grain boundaries.
|Number of pages||6|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 1999 Nov 1|
ASJC Scopus subject areas
- Ceramics and Composites