The effect of vibration ball-milling of a SiO
2-MgO powder mixture on Mg
2SiO
4 formation by a solid-state reaction between SiO
2 and MgO was examined. The results obtained are summarized as follows:
(1) It was confirmed that Mg
2SiO
4 formation during firing was accelerated by the vibro-milling of the SiO
2-MgO powder mixture. The Mg
2SiO
4 formation reaction seemed to be a diffusion controlled process regardless of the vibro-milling and firing conditions, and the rate of this reaction obeyed the Ginstling-Brounshtein equation. The apparent activation energy of this reaction decreased from 311 to 94kJ/mol with the increase in the milling time up to 120hrs.
(2) In addition to the compositional homogenization during vibro-milling, the enhancement of the SiO
2-MgO solid state reaction due to both the activation of MgO induced by amorphization during milling and the increase in the contacts between MgO and SiO
2 under the mechanical stress was thought to largely contribute to the acceleration of the Mg
2SiO
4 formation during firing.
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