LAUSR

Abstract In this paper, B4C/CrB2 ceramic composites were fabricated from a starting mixture of B4C and Cr2O3 (5–25 wt%) powders by pressureless sintering at 1600 ~ 2200 ℃ in vacuum. The phase composition, relative density, surface morphology and fracture toughness of the final ceramic composites were studied. In addition, the formation mechanism, volatilization and decomposition phenomenon of CrB2 were also detailedly investigated. Results show that the relative density and fracture toughness of the ceramic composites reach 95% and 3.36 MPa∙m1/2 respectively when sintered at 2180 ℃ with 10 wt% Cr2O3 doped. The formation of CrB2 is dominated by the direct reaction between Cr2O3 and B4C according to the thermodynamic analysis, reaction products detection and quantitative calculation. Besides, CrB2 volatilizes and decomposes at 2200 ℃ in vacuum, which decreases the relative density and fracture toughness of the B4C/CrB2 ceramic composites.