Journal of Thermal Spray Technology

, Volume 6, Issue 4, pp 439–444

Alumina-base plasma-sprayed materials—Part II: Phase transformations in aluminas

  • J. Ilavsky
  • C. C. Berndt
  • H. Herman
  • P. Chraska
  • J. Dubsky
Reviewed Paper

Abstract

Aluminum oxide is widely used for plasma spraying. Alumina deposits consist of a number of metastable crystallographic modifications, which at elevated temperatures, transform to the stable α phase. It was shown that additions of various oxides changed the phase composition and shift phase transformation temperatures. This paper addresses the variation of phase compositions and temperatures of the phase changes for plasma-sprayed alumina deposits manufactured with alumina-base materials containing O2O3 and TiO2.

This study combines the results obtained from energy dispersive analyzer of X-rays (EDAX) and scanning electron microscopy (SEM) chemical analysis, differential thermal analysis (DTA), and X-ray powder diffrac-tion (XRD) quantitative phase analysis of as-sprayed and annealed samples of alumina deposits and shows how the two additives change the phase composition and the α-phase formation temperature. This transformation temperature varied by nearly 200 °C. The metastable alumina sequences were also influenced by the chemical composition; for example, the content of 6 alumina varied between 0 and 55 wt %.

Keywords

alumina oxide ceramics phase composition phase stability plasma spray 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    N.N. Ault, Characteristics of Refractory Oxide Coatings Produced by Flame-Spraying, J. Am. Ceram. Soc., Vol 40,1957, p 69–74CrossRefGoogle Scholar
  2. 2.
    E. Dörre and H. Hübner, Alumina Processing, Properties, and Appli- cations, Springer-Verlag, Berlin, 1984, p 20–40Google Scholar
  3. 3.
    Powder Diffraction File, Alphabetical index, JCPDS, International Center for Diffraction Data, PA, USA, 1986Google Scholar
  4. 4.
    H. Herman, Plasma-Sprayed Coatings, Sci. Am., Vol 259 (No. 3), 1988, p 112–117CrossRefGoogle Scholar
  5. 5.
    P. Raus and P. Chráska, Transmission Electron Microscope Study of a Plasma-Sprayed Zircon Coating, Ceramics (Silicaty), Vol 33 (No. 4), 1989, p 325–332 (in Czechoslovakian)Google Scholar
  6. 6.
    P. Chráska, J. Dubsky, B. Kolman, J. Ilavsky, and J. Forman, Study of Phase Changes in Plasma-Sprayed Deposits, J. Therm. Spray Tech- nol., Vol 1 (No. 4), 1992, p 301–306Google Scholar
  7. 7.
    I.A. Fisher, Variables Influencing the Characteristics of Plasma- Sprayed Coatings, Int. Met. Rev., Vol 17, 1972, p 117–129Google Scholar
  8. 8.
    C.X. Ding, R.A. Zatorski, and H. Herman, Oxide Powders for Plasma Spraying—The Relationship Between Powder Charac- teristics and Coating Properties, Thin Solid Films, Vol 118, 1984, p 467–475CrossRefGoogle Scholar
  9. 9.
    J. Dubsky, B. Kolman, and P. Chráska, Influence of Cooling Rate on Phase Transformation in Alumina, Proc. of 7th Metallographic Sym- posium, Part 1, Czech Society for Sciences and Technology, High Ta- tras, Czechoslovakia, Kosice, 1989, p 168–171Google Scholar
  10. 10.
    G.N. Heintze and S. Uematsu, Preparation and Structures of Plasma- Sprayed β- and α-Al2O3 Coatings, Surf. Coat. Technol., Vol 50, 1992, p 213–222CrossRefGoogle Scholar
  11. 11.
    M. Kumagain and G.L. Messing, Enhanced Densification of Boehmite Sol-Gel by α-Alumina Seeding, J. Am. Ceram. Soc., Vol 67, 1984, p C230-C231CrossRefGoogle Scholar
  12. 12.
    G.L. Messing, M. Kumagai, R.A. Shellman, and J.L. McArdle, Seeded Transformation for Microstructural Control of Ceramic, The Science of Ceramic Chemical Processing, L.L. Hench and D.R. Ultrich, Ed., Wiley, 1986, p 259–271Google Scholar
  13. 13.
    G.C. Bye and G.T. Sympkin, Influence of Cr and Fe on Formation of α- Al2O3 from β-Al2O4, J. Am. Ceram. Soc., Vol 57, 1974, p 367–371CrossRefGoogle Scholar
  14. 14.
    T. Tushida, R. Furiuchi, T. Ishii, and K. Itoh, The Effect of Cr3+ and Fe3+ Ions on the Transformation of Different Aluminum Hydroxides to (αAl2O3, Thermochim. Acta, Vol 64, 1983, p 337–353CrossRefGoogle Scholar
  15. 15.
    I.A. Bonder, V.B. Glushkova, and P.A. Ceitlin, Study of Phase Transi- tions in Alumina, Inorganic Mater. (Neorganiceskie Materialy), Vol 7, 1971, p l367–1371Google Scholar
  16. 16.
    L. Giachetti and N. Tozzi, Quantitative Powder X-Ray Diffrac- tion of Some Ceramic Materials, Mater. Sci. Monography, Vol 16, 1983, p 185–195Google Scholar
  17. 17.
    R. Fillit, P. Homerin, J. Shafer, H. Bruyas, and F. Thevenot, Quantita- tive XRD Analysis of Zirconia-Toughened Alumina Ceramics, J. Ma- ter. Sci., Vol 22, 1987, p 3566–3570CrossRefGoogle Scholar
  18. 18.
    H.K. Schmidt, Quantitative Analysis of Polymorphic Mixes of Zir- conia by X-Ray Diffraction, J. Am. Ceram. Soc., Vol 70 (No. 5), 1987, p 367–376CrossRefGoogle Scholar
  19. 19.
    J. Wang, C.B. Poton, and P.M. Marquis, A Quantitative X-Ray Diffrac- tion Phase Analysis in the Reaction-Sintered Mullite Ceramic, J. Ma- ter. Sci. Lett., Vol 11, 1992, p 1301–1304CrossRefGoogle Scholar
  20. 20.
    J. Ilavsky, Studies of Plasma-Sprayed Alumina, dissertation, State Uni- versity of New York, UMI, No. 9500218, 1994Google Scholar
  21. 21.
    N. Iwamoto, Y. Makino, and Y. Arata, “Crystallographical Considera- tions of Sprayed Alumina,” Paper 66, presented at 9th International Thermal Spraying Conference, (Hague, Netherlands), 1980Google Scholar
  22. 22.
    C. Misra, Activated Aluminas, Industrial Alumina Chemicals, ACS Monograph 184, American Chemical Society, 1986, p 73–106Google Scholar

Copyright information

© ASM International 1997

Authors and Affiliations

  • J. Ilavsky
    • 1
  • C. C. Berndt
    • 2
  • H. Herman
    • 2
  • P. Chraska
    • 1
  • J. Dubsky
    • 1
  1. 1.Czech Academy of SciencesInstitute of Plasma PhysicsPragueCzech Republic
  2. 2.Thermal Spray LaboratoryState University of New YorkStony BrookUSA

Personalised recommendations