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Laboratory annealing experiments of refractory silicate grain analogs using differential scanning calorimetry
Author(s) -
KIMURA Yuki,
NUTH III Joseph A.,
TSUKAMOTO Katsuo,
KAITO Chihiro
Publication year - 2011
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.1945-5100.2010.01143.x
Subject(s) - differential scanning calorimetry , forsterite , crystallization , nucleation , materials science , amorphous solid , silicate , annealing (glass) , exothermic reaction , analytical chemistry (journal) , chemical engineering , mineralogy , crystallography , chemistry , thermodynamics , metallurgy , physics , organic chemistry , chromatography , engineering
– Exothermic reactions during the annealing of laboratory synthesized amorphous magnesium‐bearing silicate particles used as grain analogs of cosmic dust were detected by differential scanning calorimetry (DSC) in air. With infrared spectroscopy and transmission electron microscopy, we show that cosmic dust could possibly undergo fusion to larger particles, with oxidation of magnesium silicide and crystallization of forsterite as exothermic reactions in the early solar system. The reactions begin at approximately 425, approximately 625, and approximately 1000 K, respectively, and the reaction energies (enthalpies) are at least 727, 4151, and 160.22 J g −1 , respectively. During the crystallization of forsterite particles, the spectral evolution of the 10 μm feature from amorphous to crystalline was observed to begin at lower temperature than the crystallization temperature of 1003 K. During spectral evolution at lower temperature, nucleation and/or the formation of nanocrystallites of forsterite at the surface of the grain analogs was observed.