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Nucleation and Growth of Silicon Oxynitride Grains in a Fine‐Grained Silicon Nitride Matrix
Author(s) -
Wang Chongmin,
Emoto Hideyuki,
Mitomo Mamoru
Publication year - 1998
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.1151-2916.1998.tb02459.x
Subject(s) - nucleation , materials science , crystallography , microstructure , transmission electron microscopy , silicon , amorphous solid , silicon nitride , annealing (glass) , grain growth , silicon oxynitride , phase (matter) , epitaxy , mineralogy , nanotechnology , composite material , layer (electronics) , chemistry , metallurgy , organic chemistry
Annealing induces significant microstructural changes in β‐Si 3 N 4 ceramics densified with a silica containing additive, as signified by the precipitation of elongated Si 2 N 2 O grains in the fine‐grained β‐Si 3 N 4 matrix, leading to a reinforced structure. The phases and microstructure evolution and the interface structural features in this composite system have been systematically studied by using X‐ray diffraction, and conventional and high‐resolution transmission electron microscopy. Traced from the indispensable features of the Si 2 N 2 O grains, typically the spatial distribution of the stacking faults and the size, morphology, phase, and the spatial distribution of the particles trapped within the Si 2 N 2 O, it has been generally established that Si 2 N 2 O grains nucleate heterogeneously on the β‐Si 3 N 4 grain surface and grow rather quickly. The low nucleation rate and high growth speed of Si 2 N 2 O indicate a high nucleation barrier of Si 2 N 2 O and fast diffusion of (N,O) in the liquid. Experimentally, no epitaxial orientation relationship between Si 2 N 2 O grains and intragranularly trapped β‐Si 3 N 4 grains which either serve as a nucleation site for Si 2 N 2 O or are simply encapsulated during Si 2 N 2 O grain growth can be observed; instead, the interface between the Si 3 N 4 and the Si 2 N 2 O features an amorphous phase of uneven thickness. Sialon polytypoid phase particles similarly trapped in Si 2 N 2 O show an epitaxial relationship with Si 2 N 2 O grains. From the observed interface structure between the Si 2 N 2 O and β‐Si 3 N 4 , a possible partial ordering of a glass film in the form of Si 2 N 2 O is also discussed.