Advertisement

Journal of Materials Science

, Volume 32, Issue 5, pp 1365–1370 | Cite as

Catalytic effects of Ag2O additives on microstructure and recrystallization in borate glasses

  • S RAM
  • K RAM
Article

Abstract

A substitution of Ag2O for B2O3 in a 35BaO–25Fe2O3–(40−x)B2O3–xAg2O, x=0.0, 0.5, 1.0

and 3.0, glass series modifies the B2O3 network and changes infrared frequencies in the 1600–600 cm-1 region. Four bands at 1440, 1280, 1180 and 1120 cm-1 appear in glass containing no Ag2O additive. On adding the Ag2O, the 1120 cm-1 band (which belongs to the BO3→BO4 modified group in the B2O3 network) no longer appears, and the other three bands (belonging to the B–O stretching vibrations in the interconnected boroxol rings) shift 15–40 cm-1 to higher frequencies expected in the reduced structural defects of BO3→BO4 modified groups and non-bridging oxygens. This modified glass crystallizes (at 500–850°C) into acicular BaFe12O19 microcrystals of a higher coercivity of ∼5000 Oe, suitable for high energy-density magnets and other devices.

Keywords

Boron Atom Borate Glass BaFe Band Group Glass Series 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    F. L. Galeener and M. F. Thorpe, Phys. Rev. B 28 (1983) 5802.CrossRefGoogle Scholar
  2. 2.
    E. I. Kamitsos, J. Phys. Chem. 93 (1989) 1604.CrossRefGoogle Scholar
  3. 3.
    R. A. Barrio, F. L. C. Alvarado and F. L. Galeener, Phys. Rev. B 44 (1991) 7313.CrossRefGoogle Scholar
  4. 4.
    A. K. Hassan, L. M. Torell, L. BÖrjesson and H. W. Doweldar, ibid. 45 (1992) 12797.CrossRefGoogle Scholar
  5. 5.
    Y. Inagaki, H. Maekawa, T. Yokokawa and S. Shimokawa, ibid. 47 (1993) 674.CrossRefGoogle Scholar
  6. 6.
    S. Ram, D. Chakravorty and D. Bahadur, J. Magn. Magn. Mater. 62 (1986) 221.CrossRefGoogle Scholar
  7. 7.
    S. Ram, D. Bahadur and D. Chakravorty, ibid. 67 (1987) 378.CrossRefGoogle Scholar
  8. 8.
    M. Irion, M. Couzi, A. Levasseur, J. M. Reau and J. C. Brethous, J. Non-Cryst. Solids 31 (1980) 285.Google Scholar
  9. 9.
    J. Krogh-Moc, Phys. Chem. Glasses 6 (1965) 46.Google Scholar
  10. 10.
    S. Ram and K. Ram, J. Mater. Sci. 23 (1988) 4541.CrossRefGoogle Scholar
  11. 11.
    Idem, Infrared Phys. 29 (1989) 895.CrossRefGoogle Scholar
  12. 12.
    E. I. Kamitsos, G. D. Chryssikos, A. P. Patsis and M. A. Karakassides, J. Non-Cryst. Solids 131 (1991) 1092.CrossRefGoogle Scholar
  13. 13.
    B. Wang, S. P. Szu and M. Greenblatt, ibid. 134 (1991) 249.CrossRefGoogle Scholar
  14. 14.
    K. Haneda and A. H. Morrish, IEEE Trans. Magn. 25 (1989) 2597.CrossRefGoogle Scholar
  15. 15.
    S. Ram and J. C. Joubert, ibid. 28 (1992) 15.CrossRefGoogle Scholar
  16. 16.
    C. H. L. Goodman, Nature 257 (1975) 370.CrossRefGoogle Scholar
  17. 17.
    Idem, Phys. Chem. Glasses 26 (1985) 1.Google Scholar
  18. 18.
    W. Soppe, F. Aldenkamp and H. W. Den Hartog, J. Non-Cryst. Solids 91 (1987) 351.CrossRefGoogle Scholar
  19. 19.
    S. Ram, Phys. Rev. B 51 (1995) 6280.CrossRefGoogle Scholar
  20. 20.
    R. Barham, Can. J. Chem. 52 (1974) 3235.CrossRefGoogle Scholar
  21. 21.
    S. Ram, J. Magn. Magn. Mater. 82 (1989) 129.CrossRefGoogle Scholar
  22. 22.
    M. Fujii, M. Wada, S. Hayashi and K. Yamamoto, Phys. Rev. B 46 (1992) 15930.CrossRefGoogle Scholar

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • S RAM
    • 1
  • K RAM
    • 2
  1. 1.Institute of Metal ResearchTechnical University of BerlinBerlinGermany
  2. 2.Infrared LaboratoryDMSRDE KanpurKanpurIndia

Personalised recommendations