Preparation and mechanical properties of ZrB2-based ceramics using MoSi2 as sintering aids

ZrB₂ (zirconium diboride)-based ceramics reinforced by 15vol.% SiC whiskers with high density were successfully prepared using MoSi₂ as sintering aids. The effects of sintering condition and MoSi₂ content on densification behavior, phase composition, and mechanical properties of SiC_w/ZrB₂ composites were studied. Nearly, fully dense materials (relative density >99%) were obtained by hot-pressing (HP) at 1700°C–1800°C in flow argon atmosphere. The grain size of ZrB₂ phase in the samples sintered by HP at 1700°C–1800°C were very fine, with mean size below 5 μm. Mechanical properties (such as flexural strength, fracture toughness, and Vickers hardness) of the sintered samples were measured. The sample with 15vol.% MoSi₂ addition sintered by HP at 1750°C displayed the best mechanical properties.