Polytypism in Magnesium Sialon

  • David R. Clarke
  • T. M. Shaw
Part of the Materials Science Research book series (MSR, volume 11)


The crystallography and morphology of the 12H and 21R polytypes in a magnesium sialon (Mg1. 86 Si 1-67Al2.4703.19N3.81)have been investigated by lattice fringe imaging and electron diffraction, Intergrowths of the two poly types occur, but since they have different crystal sizes, mismatch strains are introduced which may have a detrimental effect on mechanical properties of the material. It is concluded that careful control of the starting powders and long hotpressing times will be necessary to avoid the formation of these strained intergrowths.


Electron Diffraction Pattern Close Packed Plane Mismatch Strain Dark Fringe Close Packed Layer 
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  1. 1.
    K. H. Jack and W. I. Wilson, Nature Phys. Sci. 238, 28 (1972).Google Scholar
  2. 2.
    K. H. Jack, J. Mater. Sci. 11, 1135 (1976).CrossRefGoogle Scholar
  3. 3.
    D. P. Thompson, J. Mater. Sci. n, 1377 (1976).Google Scholar
  4. 4.
    4.K. H. Jack, Private communication.Google Scholar
  5. 5.
    D. R. Clarke, T. M. Shaw and D. P. Thompson, J. Mater. Sei., 1977, in press.Google Scholar
  6. 6.
    D. R. Clarke, J. Am. Ceram. Soc., Proc. Symp. Electron Microscopy Applied to Ceramics Practice, in press.Google Scholar
  7. 7.
    D. R. Clarke and G. Thomas, these proceedings.Google Scholar

Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • David R. Clarke
    • 1
  • T. M. Shaw
    • 2
  1. 1.Rockwell International Science CenterThousand OaksUSA
  2. 2.University of CaliforniaBerkeleyUSA

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