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A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si 3 N 4 Whiskers
Author(s) -
Saeedifar Zahra
Publication year - 2018
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201700297
Subject(s) - whiskers , mesoporous material , boron carbide , sintering , boron , chemical engineering , carbothermic reaction , carbon fibers , ball mill , materials science , boric acid , carbide , whisker , chemistry , nuclear chemistry , metallurgy , composite material , catalysis , organic chemistry , composite number , engineering
Boric acid/Mg (magnesiothermic or metal sintering aid)/C (activated carbon)/N 2 or Ar (atmosphere)/additives (mesoporous SiO 2 or mesoporous SiC or SiC/Si 3 N 4 whiskers) systems were used in the one‐step synthesis of mesostructured B 4 C (221.04 m 2 /g). In this study, a mixture of the active precursors was allowed to react via a self‐sustaining reaction (high‐energy ball milling process). Also, the properties of the samples prepared using powdered activated carbon (PAC) and SiC/Si 3 N 4 whiskers (concentration in the range 5–10 wt%) as sources of carbon were investigated. X‐ray diffraction results proved the presence of crystalline boron carbide in the peak positions of B 4 C (B 12 C 3 ). The advantage of the present route for yielding mesostructured B 4 C powder seems to be limited by the growth of carbide crystals. This restriction is believed to be imposed by a lack of whisker additives around the pores where B 4 C crystals grow. The results also show that the best mesoporous additive for the synthesis of nanoscale boron carbide is mesoporous SiC. The effect of the concentration of CO (reduction of α‐Fe 2 O 3 to Fe by CO) on the B 4 C synthesis suggests that, in addition to the concentration of CO, the pressure of the N 2 atmosphere is an important factor in the synthesis of mesostructured B 4 C.