In:
Journal of Applied Physics, AIP Publishing, Vol. 106, No. 2 ( 2009-07-15)
Abstract:
Shock-recovery experiments have been performed on high-purity mullite polycrystals in the pressure range up to 72GPa. The recovered samples have been examined by an x-ray diffraction method, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. The samples shocked above 65GPa contain an amorphous SiO2 phase and a γ-Al2O3 phase, indicating that a rapid disproportionation reaction of mullite is induced by shock compression. The recovered amorphous SiO2 has a mean Si–O–Si bond angle roughly 7° narrower than that of the fused SiO2 glass, indicating the formation of the densified amorphous SiO2 phase. The γ-Al2O3 phase is crystallized as very fine particles with grain sizes less than 10nm in the matrix of the desified amorphous SiO2 phase. The crystallization of γ-Al2O3 is expected to occur during a pressure-release process owing to the crystal size effect concerning the phase stability of Al2O3.
Type of Medium:
Online Resource
ISSN:
0021-8979
,
1089-7550
Language:
English
Publisher:
AIP Publishing
Publication Date:
2009
detail.hit.zdb_id:
220641-9
detail.hit.zdb_id:
3112-4
detail.hit.zdb_id:
1476463-5
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