Microstructure and sintering mechanism of TiB2-ZrO2-SiC composite

Abstract

A ceramic TiB220 wt% (2 mol% Y2O3-ZrO2) composite has a high three-point bending strength of 1200 MPa. However, this composite lacks sinterability, so that glass encapsulation HIP'ing is required to obtain a full dense sintered compact. However, addition of 2.5-5.0 wt%SiC improved the sinterability drastically. TiB2-19.5 wt% (2 mol% Y2O3-ZrO2)-2.5 wt%SiC was densified to 96% of its theoretical density by vacuum sintering at 1700°C for 14.4 ks, and this sintered compact was hot isostatically pressed (HIP'ed) without glass encapsulation. In this work, the microstructure and sintering mechanism of TiB2-19-19.5 wt% (2 mol% Y2O3-ZrO2)-2.5-5.0 wt% SiC were investigated. TiB219-19.5 wt% (2 mol% Y2O3-ZrO2)-2.5-5.0 wt% SiC was densified drastically above 1600°C. TiB2-19-19.5 wt% (2 mol% Y2O3-ZrO2)-2.5-5.0 wt% SiC. Therefore, SiC improved the sinterability of TiB2, regardless of the presence of ZrO2.