Polymer‐Derived SiC/B4C/C Nanocomposites: Structural Evolution and Crystallization Behavior |
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| Authors: | Yun Jiang Junfei Li Farong Huang Yan Zhou Lei Du |
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| Affiliation: | Key Laboratory of Specially Functional Polymeric Materials and Related Technology of Ministry of Education, Institute of Material Science and Engineering, East China University of Science and Technology, , Shanghai, 200237 China |
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| Abstract: | Structural evolution and crystallization behavior between 600°C and 1450°C during the preparation of bulk SiC/B4C/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 B4C nanocrystallites generate at 1300°C. The sizes of β‐SiC and B4C 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. |
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