Boro/carbothermal reduction co-synthesis of dual-phase high-entropy boride-carbide ceramics. Issue 6 (June 2023)

• Record Type: Journal Article
• Authors: Feng, Lun; Fahrenholtz, William G.; Hilmas, Gregory E.; Curtarolo, Stefano
• Is Part Of: Journal of the European Ceramic Society. Volume 43:Issue 6(2023)
• Page Start: 2708
• Page End: 2712
• Publication Date: 2023-06
• Subjects: Ultra-high temperature ceramics -- High-entropy boride -- High-entropy carbide -- Microstructure -- Vickers hardness; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2022.12.056
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Dense, dual-phase (Cr, Hf, Nb, Ta, Ti, Zr)B2 -(Cr, Hf, Nb, Ta, Ti, Zr)C ceramics were synthesized by boro/carbothermal reduction of oxides and densified by spark plasma sintering. The high-entropy carbide content was about 14.5 wt%. Grain growth was suppressed by the pinning effect of the two-phase ceramic, which resulted in average grain sizes of 2.7 ± 1.3 µm for the high-entropy boride phase and 1.6 ± 0.7 µm for the high-entropy carbide phase. Vickers hardness values increased from 25.2 ± 1.1 GPa for an indentation load of 9.81 N to 38.9 ± 2.5 GPa for an indentation load of 0.49 N due to the indentation size effect. Boro/carbothermal reduction is a facile process for the synthesis and densification of dual-phase high entropy boride-carbide ceramics with both different combinations of transition metals and different proportions of boride and carbide phases.