Publication Date:
2011-09-04
Description:
The influence of carbon impurities on phase composition, microstructure, and mechanical properties of hot-pressed ZrB 2 –SiC ceramics was studied. Carbon was either present in the starting ZrB 2 powders or introduced due to the carbon-rich sintering environment. Carbon present in the starting ZrB 2 powders removed the inherent oxygen impurities to enable ceramics that appeared phase pure by X-ray diffraction, had smaller average grain sizes, and had higher Vickers’ hardness, but lower fracture toughness. Carbon introduced from the sintering environment led to the formation of secondary ZrC , allowed the microstructure to coarsen, and decreased the fracture toughness. This study showed that ZrB 2 –SiC ceramics with refined microstructure could be obtained by introducing carbon impurities in the starting ZrB 2 powders, whereas the densification should be carried out at lower temperature to avoid the carbon uptake from sintering environment.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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