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Combined Effects of Boron Carbide, Silicon, and MWCNT s in Alumina‐Carbon Refractories on Their Microstructural Evolution
Author(s) -
Liao Ning,
Li Yawei,
Jin Shengli,
Xu Yibiao,
Sang Shaobai,
Deng Zhaojun
Publication year - 2017
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.14543
Subject(s) - microstructure , transmission electron microscopy , materials science , scanning electron microscope , carbon nanotube , chemical engineering , carbon fibers , phase (matter) , carbide , boron carbide , composite number , boron , silicon carbide , nanotechnology , composite material , chemistry , organic chemistry , engineering
The phase and microstructure evolutions of multiwalled carbon nanotubes ( MWCNT s) in B 4 C‐ and Si‐containing Al 2 O 3 –C specimens under elevated temperatures were investigated by means of X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results show that the incorporation of B 4 C decreases the partial pressure of SiO(g) in Al 2 O 3 –C specimens due to the oxidation of B 4 C prior to Si at lower temperature, which prevents the transformation of MWCNT s at 1000°C and suspends the transformation under higher temperature. B 2 O 3 vapor resulting from oxidation of B 4 C powder reacts with C sources to generate nanoscaled B 4 C droplets, which facilitate the catalytic formation of new MWCNT s and nano onion‐like carbon. In addition, B‐doped MWCNT s and BN tubes with the coexistence of B 2 O 3 , MWCNT s, and N 2 are obtained under evaluated temperatures.