Advertisement

Journal of Materials Science

, Volume 30, Issue 6, pp 1561–1564 | Cite as

Thermal properties and devitrification behaviour of (1+x)CaO·(1−x)MgO·2SiO2 glasses

  • A. Costantini
  • F. Branda
  • A. Buri
Papers

Abstract

The thermal properties (glass transformation, Tg, and softening, Ts, temperatures), the crystalline phases formed during heating in a differential thermal analysis (DTA) apparatus, the kinetic parameters and the mechanism of the devitrification process, of glasses of the system diopside-wollastonite were investigated. The substitution of CaO by MgO induces an increase in Tg and the crystal growth activation energy, Ec; this is probably linked to the greater coordination number of Caz+ ions with respect to the Mg2+ ions. The substitution of CaO by MgO lowers the nucleation rates of the diopside phase; wollastonite solid solution nuclei form whose growth appears to leave a glassy matrix in which diopside formation is inhibited. Only surface nucleation was observed, but, in finely powdered samples, which soften and efficiently sinter before devitrifying, surface nuclei behave as bulk nuclei. When bulk crystallization occurs, the Avrami parameter m was found to be 2 for all glasses, except the diopside one, for which m=3.

Keywords

Activation Energy Thermal Property Differential Thermal Analysis Coordination Number Nucleation Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    L. L. Hench, J. Am. Ceram. Soc. 74 (1991) 1487.CrossRefGoogle Scholar
  2. 2.
    T. Kokubo, Bol. Soc. Esp. Ceram. Vid. (Proc. XVI International Congress on Glass, Vol. I) 31-C1 (1992) 119.Google Scholar
  3. 3.
    Z. Strnad, “Glass-Ceramic Materials” (Elsevier, Amsterdam, 1986) p. 110.Google Scholar
  4. 4.
    E. M. Levin, C. R. Robins and H. F. McMurdie “Phase diagrams for Ceramists” (The American Ceramics Society, Columbus, OH, 1964) P. 211.Google Scholar
  5. 5.
    K. Matusita and S. Sakka, Bull. Inst. Chem. Res. Kyoto Univ. 59 (1981) 159.Google Scholar
  6. 6.
    D. R. MacFarlane, M. Matecki and M. Poulain, J. Non-Cryst. Solids 64 (1984) 351.CrossRefGoogle Scholar
  7. 7.
    P. G. Boswell, J. Thermal Anal. 18 (1980) 353.CrossRefGoogle Scholar
  8. 8.
    H. J. Borchardt and F. Daniels, J. Am. Chem. Soc. 79 (1957) 41.CrossRefGoogle Scholar
  9. 9.
    K. Akita and M. Kase, J. Phys. Chem. 72 (1968) 906.CrossRefGoogle Scholar
  10. 10.
    F. O. Piloyan, I. V. Ryabchica and O. S. Novikova, Nature 212 (1966) 1229.CrossRefGoogle Scholar
  11. 11.
    N. H. Ray, J. Non-Cryst. Solids 15 (1974) 423.CrossRefGoogle Scholar
  12. 12.
    H. Rawson, “Inorganic Glass Forming Systems” (Academic Press, London, New York, 1967) p. 24.Google Scholar
  13. 13.
    A. Costantini, F. Branda and A. Buri, J. Eur. Ceram. Soc., in press.Google Scholar
  14. 14.
    F. Branda, A. Costantini and A. Buri, Thermochim. Acta 217 (1993) 207.CrossRefGoogle Scholar
  15. 15.
    F. Branda, A. Costantini, A. Buri and A. Tomasi, J. Thermal Anal. 41 (1994) 1979.CrossRefGoogle Scholar
  16. 16.
    A. N. Winchell and H. Winchell, “The microscopical characters of artificial inorganic substances: optical properties of artificial minerals” (Academic Press, New York, London, 1964) p. 291.Google Scholar
  17. 17.
    E. D. Zanotto, J. Non-Cryst. Solids 130 (1991) 217.CrossRefGoogle Scholar
  18. 18.
    K. Maeda, E. Ichikura, Y. Nakao and S. Ito, Bol. Soc. Esp. Ceram. Vid. (Proc. XVI International Congress on Glass, Vol. 5) 31-C (1992) 15.Google Scholar

Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • A. Costantini
    • 1
  • F. Branda
    • 1
  • A. Buri
    • 1
  1. 1.Dipartimento di Ingegneria dei Materiali e della ProduzioneUniversità “Federico II”NapoliItalia

Personalised recommendations