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Low‐temperature crystallization of MgSiO 3 glasses under electron irradiation: Possible implications for silicate dust evolution in circumstellar environments
Author(s) -
CARREZ Philippe,
DEMYK Karine,
LEROUX Hugues,
CORDIER Patrick,
JONES Anthony P.,
D'HENDECOURT Louis
Publication year - 2002
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2002.tb00815.x
Subject(s) - crystallization , crystallite , amorphous solid , materials science , nucleation , silicate , irradiation , ion , transmission electron microscopy , forsterite , analytical chemistry (journal) , mineralogy , crystallography , chemical engineering , chemistry , nanotechnology , physics , metallurgy , organic chemistry , chromatography , nuclear physics , engineering
— Synthetic MgSiO 3 glasses were irradiated at room temperature by 300 keV electrons in a transmission electron microscope (TEM). One of the samples had been previously irradiated by 50 keV He+ ions. Electron irradiation induces the nucleation and growth of randomly oriented nanometer‐sized crystallites. The crystallites first consist of MgO and subsequently of forsterite (Mg 2 SiO 4 ). Both are seen to form within an amorphous SiO 2 matrix. The rate of crystallization of the samples has been monitored by conventional TEM imaging and electron diffraction. The sample that had been pre‐irradiated with He+ ions is found to transform faster than the as‐quenched glass. The crystallization of metastable MgSiO 3 glasses is explained by ionizing radiation‐induced elemental diffusion that allows the reorganization of matter into a more favourable thermodynamic state. These results show that ionizing radiation interactions could account for crystal formation as observed in infrared spectroscopy in some young stellar environments.