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Papers by ngeleshi kibambe
Ceramics International, 2012
ZrC-SiC ceramics were fabricated by high-energy ball milling and reactive hot pressing of ZrH 2 ,... more ZrC-SiC ceramics were fabricated by high-energy ball milling and reactive hot pressing of ZrH 2 , carbon black, and varying amounts of SiC. The ceramics were composed of nominally pure ZrC containing 0 to 30 vol% SiC particles. The relative density increased as SiC content increased, from 96.8% for nominally pure ZrC to 99.3% for ZrC-30 vol% SiC. As SiC content increased from 0 to 30 vol%, Young's modulus increased from 404±11 to 420±9 GPa Accepted Article This article is protected by copyright. All rights reserved. and Vickers hardness increased from 18.5±0.7 to 23.0±0.5 GPa due to a combination of the higher relative density of ceramics with higher SiC content and the higher Young's modulus and hardness of SiC compared to ZrC. Flexure strength was 308±11 MPa for pure ZrC, but increased to 576±49 MPa for a SiC content of 30 vol%. Fracture toughness was 2.3±0.2 MPa•m 1/2 for pure ZrC and increased to about 3.0±0.1 MPa•m 1/2 for compositions containing SiC additions. The combination of high-energy ball milling and reactive hot pressing was able to produce ZrC-SiC ceramics with sub-micron grain sizes and high relative densities with higher strengths than previously reported for similar materials.
Ceramics International, 2012
ZrC-SiC ceramics were fabricated by high-energy ball milling and reactive hot pressing of ZrH 2 ,... more ZrC-SiC ceramics were fabricated by high-energy ball milling and reactive hot pressing of ZrH 2 , carbon black, and varying amounts of SiC. The ceramics were composed of nominally pure ZrC containing 0 to 30 vol% SiC particles. The relative density increased as SiC content increased, from 96.8% for nominally pure ZrC to 99.3% for ZrC-30 vol% SiC. As SiC content increased from 0 to 30 vol%, Young's modulus increased from 404±11 to 420±9 GPa Accepted Article This article is protected by copyright. All rights reserved. and Vickers hardness increased from 18.5±0.7 to 23.0±0.5 GPa due to a combination of the higher relative density of ceramics with higher SiC content and the higher Young's modulus and hardness of SiC compared to ZrC. Flexure strength was 308±11 MPa for pure ZrC, but increased to 576±49 MPa for a SiC content of 30 vol%. Fracture toughness was 2.3±0.2 MPa•m 1/2 for pure ZrC and increased to about 3.0±0.1 MPa•m 1/2 for compositions containing SiC additions. The combination of high-energy ball milling and reactive hot pressing was able to produce ZrC-SiC ceramics with sub-micron grain sizes and high relative densities with higher strengths than previously reported for similar materials.