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Materials science

Superhard ceramics

Nature volume 400, pages 312–313 (1999)Cite this article

In contrast to the polymer scientist, who has the privilege of calling upon an ever-expanding array of compositions from which to choose, the ceramic scientist has had to devote years of intensive research to the refinement of a relatively limited number of systems. So it is exciting news to hear from Zerr et al. on page 340 of this issue1 that in one of these systems — silicon nitride — a new form of compound has been found. Moreover, the new cubic compound is potentially much harder than existing phases, offering considerable industrial scope for the material.

In the ceramics community, Si3N4has enjoyed an exceptional degree of attention largely because of its potential as a material for high-temperature heat engines. The excitement arises in part from its mechanical properties, such as greater strength and ability to resist mechanical failure when subjected to sudden temperature changes. It is also less brittle than many ceramics, owing to the way in which the crystalline grains in the material become acicular (that is, length ten times greater than width); the resulting interlinking improves the resistance to mechanical failure. Ceramics are traditionally prepared from powdered materials, and Si3N4is no exception: the precursor material is shaped into a powder mass, which is then consolidated by heat treatment. A special aspect of Si3N4processing is the use of both phase types: when α powder is used, it converts during heat treatment to the β form to yield the acicular crystal morphology.

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Figure 1: Phases of silicon nitride, showing the silicon atoms in purple and the nitrogen atoms in green.

References

  1. Zerr, A. et al. Nature 400, 340–342 (1999).

    Google Scholar 

  2. Hampshire, S. Mater. Sci. Technol. 11, 119–171 (VCH, Weinheim, 1994).

    Google Scholar 

  3. Jack, K. H. in New Oxide Technical and Engineering Ceramics (ed. Hampshire, S.) 1-30 (Elsevier, London, 1986).

  4. Segal, D. Mater. Sci. Technol. 17A, 70–98 (VCH, Weinheim, 1996).

    Google Scholar 

  5. Riedel, R. Mater. Sci. Technol. 17B, 1–50 (VCH, Weinheim, 1996).

    Google Scholar 

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  1. Engineering and Physical Sciences Research Council, SN2 1ET, Swindon, UK

    R. J. Brook

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  1. R. J. Brook
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Brook, R. Superhard ceramics. Nature 400, 312–313 (1999). https://doi.org/10.1038/22422

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