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Microstructure and Growth Model for Rice‐Hull‐Derived SiC Whiskers
Author(s) -
NUTT STEVEN R.
Publication year - 1988
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.1151-2916.1988.tb05021.x
Subject(s) - whisker , whiskers , microstructure , materials science , silicon carbide , monocrystalline whisker , composite material , core (optical fiber) , silicon , mineralogy , chemical engineering , metallurgy , chemistry , engineering
The microstructure of silicon carbide whiskers grown from rice hulls has been studied using methods of high‐resolution analytical electron microscopy. Small, partially crystalline inclusions (∼10 nm) containing calcium, manganese, and oxygen are concentrated in whisker core regions, while peripheral regions are generally inclusion free. The distinct microphase distribution is evidence of a two‐stage growth process in which the core region grows first, followed by normal growth toward whisker sides. Partial dislocations extend radially from the core region to the surface and tend to be paired in V‐shaped configurations. Whisker surfaces exhibit microroughness due to a tendency to develop small facets on close‐packed planes. The microstructural data obtained from TEM observations are used as a basis for discussion of the mechanisms involved in whisker growth, and a model of the growth process is proposed. The model includes a two‐dimensional growth mechanism involving vapor, liquid, and solid phases, although it is significantly different from the classical vapor‐liquid‐solid (VLS) process of whisker growth.