Kinetic vs. thermodynamic control of crystal nucleation and growth in molten silicates |
| |
Authors: | Mathieu Roskosz Michael J Toplis Pascal Richet |
| |
Institution: | a Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015-1305, USA b CRPG, CNRS, UPR 2300, 15 Rue Notre-dame des Pauvres, BP 20, 54501 Vandoeuvre-lès-Nancy Cedex, France c DTP, Observatoire Midi-Pyrénées, 14 Avenue Edouard Belin, 31400 Toulouse, France d Physique des Minéraux et des Magmas, Institut de Physique du Globe, 4 place Jussieu, 75252 Paris Cedex 05, France |
| |
Abstract: | A series of calcium aluminosilicate liquids have been experimentally heat-treated at high but variable states of undercooling, from just above the glass transition to the vicinity of the solidus. The mineralogy and chemistry of crystalline phases which appear in these experiments have been quantified using a combination of Transmission Electron Microscopy and Raman spectroscopy. The results show that mineral compositions are highly variable as a function of temperature, but that changes are governed by the contrasting and strongly temperature-dependent mobilities of network-modifying and network-forming cations. Whereas equilibrium crystals form near the liquidus, disordered and non-stoichiometric phases precipitate near the glass transition. Despite this apparently complex situation, the relative importance of thermodynamic and kinetic factors is found to be a single function of T − Tg (where T is temperature and Tg the glass transition temperature), regardless of the silicate composition. The existence of this mastercurve may be used to control the composition of novel composite materials such as glass ceramics. |
| |
Keywords: | Crystallization Transport properties - liquids STEM/TEM Silicates |
本文献已被 ScienceDirect 等数据库收录! |
|