Journal of Materials Science

, Volume 19, Issue 5, pp 1726–1736 | Cite as

Diffraction studies of β″-magnesium sialon

  • G. Leng-Ward
  • M. H. Lewis
  • S. Wild


The compositions of high magnesium content β″-magnesium sialon crystals within the 3M/4X plane of the Mg-Si-Al-O-N system indicate some form of metal atom ordering wihtin the β″ structure. Although it is not possible using X-ray diffraction to detect weak additional reflections arising from the ordering between magnesium, aluminium, and silicon atoms, such weak reflections are revealed on electron diffraction photographs for a β″ phase, resulting in a tripling of the hexagonal latticec-dimension. These show β″ to have a structure very similar to rhombohedral willemite (Zn2SiO4), with the (Mg, Al) metal atoms ordered with respect to the silicon atoms in a 2∶1 ratio. However, there are some additional weak diffraction spots with indices not obeying the rhombohedral condition of −h+k+l=3n. It is proposed that the structure of this β″ is identical to that of willemite and the extra spots are a result of some form of twinning, which implies the existence of “ordered microdomains”.


Magnesium Hexagonal Electron Diffraction Metal Atom Diffraction Study 
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Copyright information

© Chapman and Hall Ltd. 1984

Authors and Affiliations

  • G. Leng-Ward
    • 1
  • M. H. Lewis
    • 2
  • S. Wild
    • 3
  1. 1.Department of SciencePolytechnic of WalesPontypriddUK
  2. 2.Department of PhysicsUniversity of WarwickCoventryUK
  3. 3.Department of Civil Engineering and BuildingPolytechnic of WalesPontypriddUK

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