Evolution of the Ni2+ Environment During the Formation of a MgOAl2O3SiO2 Glass-Ceramic: A Combined XRD and Diffuse Reflectance Spectroscopy Approach

Authors

  • Aymeric Dugué,

    1. Institut de minéralogie et de physique des milieux condensés, Université Pierre et Marie Curie, CNRS, Paris, France
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  • Laurent Cormier,

    Corresponding author
    • Institut de minéralogie et de physique des milieux condensés, Université Pierre et Marie Curie, CNRS, Paris, France
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    • Member, The American Ceramic Society.
  • Olivier Dargaud,

    1. Institut de minéralogie et de physique des milieux condensés, Université Pierre et Marie Curie, CNRS, Paris, France
    2. Cité de la Céramique, Sèvres, France
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  • Laurence Galoisy,

    1. Institut de minéralogie et de physique des milieux condensés, Université Pierre et Marie Curie, CNRS, Paris, France
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  • Georges Calas

    1. Institut de minéralogie et de physique des milieux condensés, Université Pierre et Marie Curie, CNRS, Paris, France
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    • Member, The American Ceramic Society.

Author to whom correspondence should be addressed. e-mail: cormier@impmc.upmc.fr

Abstract

The effect of the addition of NiO on the crystallization mechanisms has been studied for SiO2Al2O3MgO glass-ceramics. A detailed Rietveld analysis has been made to determine the chemical composition and the cation distribution in the spinel phase and the evolution of Ni2+ coordination site using diffuse reflectance spectroscopy. Powder X-ray diffraction (XRD) results show the formation of β-quartz and spinel and the nickel fraction in the spinel phase decreasing as the plateau temperature increases. The determination of cation distribution in spinel using XRD reveals a preference of Ni2+ and Al3+ for octahedral sites and an increasing proportion of Ni2+ in tetrahedral sites for heat treatments at high temperature (1100°C–1200°C). Diffuse reflectance spectroscopy shows that Ni2+ is mainly fivefold coordinated in the starting glass, playing an important role in the crystallization of the spinel phase and it confirms the presence of tetrahedral and octahedral Ni2+ in the glass-ceramics. The combination of these two techniques also indicates a chemical heterogeneity of spinel crystals with Ni2+-rich and Mg2+-rich zones.

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