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Detection of Boron Segregation to Grain Boundaries in Silicon Carbide by Spatially Resolved Electron Energy‐Loss Spectroscopy
Author(s) -
Gu Hui,
Shinoda Yutaka,
Wakai Fumihiro
Publication year - 1999
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.1551-2916.1999.tb20089.x
Subject(s) - grain boundary , boron , materials science , electron energy loss spectroscopy , silicon , boron oxide , silicon carbide , analytical chemistry (journal) , spectroscopy , carbide , grain boundary diffusion coefficient , chemical physics , crystallography , oxide , metallurgy , nanotechnology , chemistry , microstructure , transmission electron microscopy , physics , organic chemistry , chromatography , quantum mechanics
Boron segregation to grain boundaries in SiC was directly observed for the first time by using spatially resolved electron energy‐loss spectroscopy methods. The hot‐pressed, fully dense material was doped with 0.3 wt% of boron and was free of other additives, except for 2 wt% of free carbon. The detection of boron was achieved in the difference spectra at all the grain boundaries that were examined. Its interfacial excess was in the range of 15–29 atoms/nm 2 , or approximately one monolayer. Concurrently, silicon depletion occurred at these boundaries, although to a lesser extent (−13.5 atoms/nm 2 on average), which indicated that boron mainly replaces silicon and bonds with carbon at the grain boundary. These findings validate the dual role of boron at the grain boundary for promoting densification via improved grain‐boundary diffusivity while maintaining a covalent grain boundary without an oxide phase.