Premium
Effect of Carbon Impurities on Hot‐Pressed ZrB 2 –SiC Ceramics
Author(s) -
Guo WeiMing,
Yang ZhenGuo,
Zhang GuoJun
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04818.x
Subject(s) - materials science , microstructure , sintering , ceramic , carbon fibers , impurity , fracture toughness , composite material , phase (matter) , toughness , metallurgy , composite number , chemistry , organic chemistry
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 V ickers’ 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.