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Polymer‐Derived SiC / B 4 C / C Nanocomposites: Structural Evolution and Crystallization Behavior
Author(s) -
Jiang Yun,
Li Junfei,
Huang Farong,
Zhou Yan,
Du Lei
Publication year - 2014
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/jace.12670
Subject(s) - crystallization , nucleation , materials science , pyrolytic carbon , chemical engineering , crystallite , nanocrystal , amorphous solid , pyrolysis , nanocomposite , ceramic , crystallography , nanotechnology , chemistry , composite material , organic chemistry , metallurgy , engineering
Structural evolution and crystallization behavior between 600°C and 1450°C during the preparation of bulk SiC / B 4 C / C nanocomposites by the pyrolysis of CB ‐ PSA preceramic were investigated. The CB ‐ PSA preceramic converts into carbon‐rich Si – B – C ceramics up to 800°C. Structural evolution and crystallization of Si – B – C materials could be controlled by adjusting the pyrolytic temperature. The Si – B – C ceramics are amorphous between 800°C and 1000°C. Phase separation and crystallization begin at 1100°C. The crystallization of β‐ SiC takes place at 1100°C and B 4 C nanocrystallites generate at 1300°C. The sizes of β‐ SiC and B 4 C nanocrystals increase with the pyrolytic temperature rising. In addition, the boron‐doping effect on structural evolution was studied by comparing the crystallization and graphitization behavior of Si – B – C ceramics and the corresponding Si – C materials. Boron is helpful for the growth of β‐ SiC nanocrystals and the graphitization, but harmful for the nucleation of β‐ SiC crystallites.