Pressureless Sintering of Dual Phase High Entropy Boride-Carbide Ceramics
SMITH II S. 1, FAHRENHOLTZ W. 1, HILMAS G. 1
1 Missouri University of Science and Technology, Rolla, United States
Dual-phase, high-entropy boride-carbide ceramics were densified by conventional powder processing and pressureless sintering. Powders were synthesized by a two step process consisting of carbothermal reduction of oxides to form the carbide phase, then partial conversion of the carbide to boride by reaction with boron carbide. Relative densities up to ~96% were obtained for ceramics containing about 30 vol% high entropy boride and 70 vol% high entropy carbide. Isostatic pressing at 200 MPa resulted in higher relative densities of both the green bodies and final ceramics compared to uniaxial pressing. The highest relative density of 96.3% was achieved for a ceramic that was isostatically pressed at 200 MPa and sintered at 2300°C for 2 hr. Grain sizes of the resulting ceramics were ~2 µm. This presentation will discuss the processing and properties of the dual phase boride-carbide ceramics.