Tantalum Oxide-Polymer Composites

  • Stephen T. Wellinghoff
  • Scott F. Timmons
Chapter

Abstract

Ceramers made from tantalum oxide and ductile engineering thermoplastics have potential for making X-ray absorbing, chemically resistant optical elements for space uses. To fabricate these materials, powders of general composition TaxOy(OSi(Me)3)z have been made by hydrolyzing Ta(OEt)5 with formic acid in the presence of C1Si(Me)3. These powders dissolve in alcohols with the replacements of the trimethyl siloxy group with the alkoxy moiety which may be of the group ethoxy, methoxy, and methoxy ethoxy. The soluble oligomeric tantalum oxide cluster can be mixed in any proportion with methoxyethanol solutions of phenoxy (hydroxy aryl-alkyl ether) polymer to form clear solutions which can be cast into films and subsequently powdered in liquid nitrogen. The powder with tantalum oxide weight percentages less than 60% (60 Ta-40 phenoxy) can be compression molded at 150°C into plaques that are transparent to visible light above 400 nm.

Although ultraviolet-visible (UV-Vis) spectroscopy reveals no change of the chemical resistance of the 60 Ta-40 phenoxy films was tested by exposure of N2H2—H2O for 2 hr at room temperature, there are some minor changes observed in the infrared (IR) spectrum of exposed thin films.

The 60 Ta-40 phenoxy films can be cast and compression molded into plaques which have the potential for high X-ray absorption, hydrazine resistance and good mechanical and optical properties.

Keywords

Mold Ductility Oligomer Epoxide Hydrazine 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    B.M. Novak, Hybrid Nanocomposite Materials–Between Inorganic Glasses and Organic PolymersAdv. Mat., 5(6):422 (1993).CrossRefGoogle Scholar
  2. 2.
    B.M. Novak and C. Davies, Inverse Organic-Inorganic Composite Materials 2. Free-Radical Routes into Nonshrinking Sol-Gel Composites, Macromol. 24:5481 (1991).CrossRefGoogle Scholar
  3. 3.
    “Columbium and Tantalum”, F.T. Sisco and E. Epremian, eds., Wiley, New York (1963).Google Scholar
  4. 4.
    V.K. Sethi and R. Gibala, The Effect of Anodic Oxide Coatings on the Mechanical Behavior of Niobium and Tantalum Single Crystals, Thin Solid Films, 39:79 (1976).CrossRefGoogle Scholar
  5. 5.
    S.C. Lee, Effective Propagation Constant of Fibrous Media Containing Parallel Fibers in the Dependent Scattering Regime, J.Heat Transfer, 114:473 (1992).CrossRefGoogle Scholar
  6. 6.
    “International Tables for X-ray Crystallography, Vol.III”, C.H. Maegilllavrey and C.D. Rieke, eds., Kynoch Press, Birmingham, Engl. (1962).Google Scholar
  7. 7.
    D.C. Bradley and H. Holloway, Metal Oxide Alkoxide Polymers, Can. J. Chem., 39:1818 (1961).CrossRefGoogle Scholar
  8. 8.
    R.O Mehrotra and P.N. Kapoor, Alcoholysis Reactions of Niobium and Tantalum Pentaalkoxides; Reaction of Tantalum Ethoxide with Glycols, J. of Less Common Metals, 10(5):354 (1966); 10(4):237 (1966).CrossRefGoogle Scholar
  9. 9.
    R.C. Mehrotra and P.N. Kapoor, Reaction of Tantalum Ethoxide with P-oxo Esters; Reaction of Tantalum Ethoxide with Organic Esters, J.Less Common Metals, 7(6):453, (1964); 10(1):66 (1966).CrossRefGoogle Scholar
  10. 10.
    W.F. Hale, Phenoxy Resins, Encyl. Poly. Sci. Tech., 10:111 (1969).Google Scholar
  11. 11.
    H. Schmidbaur, High Resolution Nuclear Magnetic Resonance Spectra of Methyl Silicon Compounds, JACS, 85:2336 (1963).CrossRefGoogle Scholar
  12. 12.
    W. McFarlane and J.M. Seaby, Studies of Silicon-29 Chemical Shifts in Methylsilyl Carboxylates by Heteronuclear Magnetic Double Resonance, JCS, Perkins Transactions, Part II, 1561 (1972).CrossRefGoogle Scholar
  13. 13.
    L.J. Bellamy, “The Infra-red Spectra of Complex Molecules”, John Wiley, New York, (1958).Google Scholar
  14. 14.
    H. Rizkalla, Investigation into the Mechanism of Ductility of Thin Amorphous Ta205 Films, Ph.D. Thesis, University of Minnesota, (1984).Google Scholar
  15. 15.
    “Narrow Band Absorbers for Space Based Optics,” Final Report WPAFB (Honeywell Prime Contract F33615–86-C-5065, SwRI Subcontract 01–1719, April 1990).Google Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • Stephen T. Wellinghoff
    • 1
  • Scott F. Timmons
    • 1
  1. 1.Chemistry and Chemical Engineering DivisionSouthwest Research InsituteSan AntonioUSA

Personalised recommendations