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Synthesis of AlN Powder by Carbothermal Nitridation of Al2O3 at Elevated N2 Pressures

  • B. Forslund
  • J. Zheng
Chapter

Abstract

AlN is a potentially important ceramic material for use in heat engines. In this paper we report some results of synthesizing AlN powder by carbothermal reduction of Al2O3 at elevated nitrogen pressures. Small charges of C + Al2O3 powder mixtures were heat-treated (1300 – 1700°C) in a reactor permitting controlled flows of pressurized N2 (0.1 – 5 MPa) through the sample space. The samples were characterized by XRD, SEM and chemical analyses (N,O).

The rate of conversion to AlN was found to be a function of temperature, gas flow rate, C/Al2O3 ratio and also, to some extent, of nitrogen pressure.

The residual oxygen content obtained after a 1-hour run at 1600°C and 1 MPa was considerably lower (0.4 wt-%) than the corresponding value obtained at atmospheric pressure (3%2), using starting mixtures of carbon black (80 m2/g) and α-Al2O3 (0.6 m2/g).

The AlN particle size (in the range 0.5 – 3 µm) and the degree of agglomeration were also found to be dependent on gas flow rate and pressure, as well as on raw-material type.

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References

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    Sheppard, L.M.; “AlN: a Versatile but Challenging Material”, Ceramic Bull. 69(11), 1801–12 (1990).Google Scholar
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    Blakely, K.A., Schorr, J.R. and Shaffer, P.T.; “AlN Ceramics, a Potential Material for Heat Management in Internal Combustion Engines”, p. 1515 in “Ceramic Materials and Components for Engines”, ed.: V.J. Tennery, The American Ceramic Society (1989).Google Scholar
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    Shanker, K., Grenier, S. and Drew, R.A.L.; “Synthesis of Nitride Ceramics by Carbothermal Reduction”, p. 321 in “Ceramic Powder Science III”, eds.: G.L. Messing, S-I. Hirano and H. Hausner, The American Ceramic Society (1990).Google Scholar
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    Hirai, S., Miwa, T., Iwata, T. and Katayama, H.G.; “Some Examination on the Formation of AlN by Simultaneous Reduction-Nitriding of Al2O3”, JJIM 54(2), 181–5 (1990).Google Scholar
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    Kosolapova, T.Ya.; Yakovleva, D.S.; Oleinik, G.S.; Bartnitskaya, T.S.; Tel’nikova, N.P. and Timofeeva, I.I.; “Some Features of the Formation of AlN During the Reduction-Nitriding of Ultrafinely Divided Alumina”, Poroshk. Metall. 11(263), 14–9 (1984)Google Scholar

Copyright information

© Elsevier Science Publishers Ltd and MPA Stuttgart 1992

Authors and Affiliations

  • B. Forslund
    • 1
  • J. Zheng
    • 1
  1. 1.Department of Inorganic Chemistry, Arrhenius LaboratoryStockholm UniversityStockholmSweden

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