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Solid‐Sample 11 B Nuclear Magnetic Resonance and X‐ray Photoelectron Spectroscopy Study of Boron‐Doped β‐Silicon Carbide
Author(s) -
O'Donnell Daniel J.,
Cheung T. T. Peter,
Schuette George F.,
Sardashti Maziar
Publication year - 1991
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.1151-2916.1991.tb07829.x
Subject(s) - x ray photoelectron spectroscopy , boron , materials science , boron carbide , silicon , magic angle spinning , analytical chemistry (journal) , silicon carbide , sintering , scanning electron microscope , metallurgy , nuclear magnetic resonance , chemistry , nuclear magnetic resonance spectroscopy , composite material , chromatography , physics , organic chemistry
Solid‐sample magic angle spinning (MAS) nuclear magnetic resonance (NMR) and X‐ray photoelectron spectroscopy (XPS), in conjunction with scanning electron microscopy (SEM), were used to investigate the fate of boron used as a sintering aid for silicon carbide. The results of the NMR studies indicated that the boron penetrated the silicon carbide grain boundaries during sintering, and was incorporated in a tetrahedral form in the bulk, regardless of the gas used during the process. The NMR spectrum of a sample sintered under nitrogen indicated the formation of a trigonal form of boron as well. XPS identified this trigonal boron as boron nitride; however, no boron was detected by XPS in any form on the fracture surface of the silicon carbide sintered under argon, even though the NMR results confirmed the presence of tetrahedral boron in the bulk sample. The SEM results indicated that the fracture process for these materials was predominantly intergranular. This suggested that the boron in the silicon carbide sintered under argon penetrated the grains and left the grain boundaries depleted of boron.