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Grain Boundary Evolution in Hot‐Pressed ABC‐SiC
Author(s) -
Zhang Xiao Feng,
Sixta Mark E.,
Jonghe Lutgard C.
Publication year - 2000
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.1151-2916.2000.tb01637.x
Subject(s) - grain boundary , materials science , transmission electron microscopy , silicon carbide , hot pressing , amorphous solid , wurtzite crystal structure , carbide , annealing (glass) , high resolution transmission electron microscopy , silicon , metallurgy , crystallography , composite material , microstructure , nanotechnology , chemistry , zinc
Silicon carbide with aluminum, boron, and carbon additions (ABC‐SiC) was hot‐pressed to full density. The samples were examined by transmission electron microscopy (TEM), with an emphasis on high‐resolution electron microscopy (HREM). Amorphous grain boundary interlayers, typically less than 2 nm wide, were formed between SiC grains. Heat‐treating the ABC‐SiC at temperatures as low as 1100°C in Ar crystallized the grain boundary interlayers completely without significantly changing the dominant chemical constituents. Chemical microanalyses demonstrated Al and O enrichment for all examined grain boundaries in both as‐prepared and annealed samples. Quantitative EDS analyses revealed Al 2 OC‐ and Al 2 O 3 ‐related species (with Si, C, B, or S substitutions) as two of the most likely grain boundary interlayer materials, both before and after heat treatment. Al 2 O 3 , and (Al 1− x Si x ) 2 OC with a 2H‐type wurtzite structure, were identified as grain boundary films by HREM images. The structural evolution in the grain boundary phases during the hot pressing and postannealing is discussed.