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- Title
Continuous SiC Skeleton-Reinforced Reaction-Bonded Boron Carbide Composites with High Flexural Strength.
- Authors
Xia, Qian; Sun, Shihao; Ye, Jun; Zhang, Cuiping; Ru, Hongqiang
- Abstract
Reaction-bonded boron carbide (RBBC) composites have broad application prospects due to their low cost and net size sintering. The microstructure, reaction mechanism of boron carbide with molten silicon (Si), and mechanical properties have been substantially studied. However, the mechanical properties strengthening mechanism of reaction-bonded boron carbide composites are still pending question. In this study, dense boron carbide ceramics were fabricated by liquid Si infiltration of B4C-C preforms with dispersed carbon black (CB) as the carbon source. Polyethyleneimine (PEI) with a molecular weight of 1800 was used as the dispersant. CB powders uniformly distributed around boron carbide particles and efficiently protected them from reacting with molten Si. The uniformly distributed CB powders in situ reacted with molten Si and formed uniformly distributed SiC grains, thus forming a continuous boron carbide–SiC ceramic skeleton. Meanwhile, the Si content of the composites was reduced. Using PEI-dispersed CB powders as additional carbon source, the composites' flexural strength, fracture toughness, and Vickers hardness reach up to 470 MPa, 4.6 MPa·m1/2, and 22 GPa, which were increased by 44%, 15%, and 10%, respectively. The mechanisms of mechanical properties strengthening were also discussed.
- Subjects
FLEXURAL strength; BORON carbides; VICKERS hardness; FRACTURE toughness; CARBON-black; SILICON carbide
- Publication
Materials (1996-1944), 2023, Vol 16, Issue 14, p5153
- ISSN
1996-1944
- Publication type
Article
- DOI
10.3390/ma16145153