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Ceramics

Tough cookery

Nature volume 389, pages 675–677 (1997)Cite this article

Materials scientists are used to identifying a material from the shape and form of the grains in its microstructure — there is even a tendency to assume that a particular phase always occurs in the same crystal form (needles, plates, spheres ⃛). On page701 of this issue1, Chen and Rosenflanz show how this assumption is wrong in one particularly interesting case. Whereas the ceramic α-SiAlON usually occurs as equiaxial grains, it can form as needles under different conditions of nucleation and growth. This achievement is of immediate practical relevance because α-SiAlON is extremely hard — even harder than β-SiAlON, which is used to make such things as turbochargers and other engine components. But until now α-SiAlON ceramics have always been brittle, because of their equiaxial microstructure.

The search for tough ceramics is unending. Usually, if a new toughening mechanism is identified, it will only work over a limited range of temperature, or it will be at the expense of strength or hardness (see boxfor the distinctions between these three quantities). Silicon nitride and its related SiAlON ceramics2 have an advantage over competing materials (Table1) because, as well as having high strength (up to 1,000 MPa) and hardness (15-20 GPa), they can form microstructures that also have slightly better toughness (in the range 6-9 MPa m1/2); moreover, these properties are retained up to temperatures beyond 1,000 °C.

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Figure 1: Typical microstructure of a mixed α-β SiAlON ceramic.

References

  1. Chen, I.-W. & Rosenflanz, A. Nature 389, 701–704 (1997).

    Article  ADS  CAS  Google Scholar 

  2. Jack, K. H. in Progress in Nitrogen Ceramics (ed. Riley, F. L.) NATO ASI Ser. E65, 45-60 (Nijhoff, The Hague, 1983).

  3. Jack, K. H. & Wilson, W. I. Nature Phys. Sci. 238, 28–29 (1972).

    Google Scholar 

  4. Hampshire, S., Park, H. K., Thompson, D. P. & Jack, K. H. Nature 274, 880–881 (1978).

    Article  ADS  CAS  Google Scholar 

  5. Menon, M. & Chen, I.-W. J. Am. Ceram. Soc. 78, 545-552 ; 553-559 (1995).

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  1. the Department of Mechanical, Materials and Manufacturing Engineering, Old Forge Building, University of Newcastle, NE1 7RU, Newcastle-upon-Tyne, UK

    Derek Thompson

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Thompson, D. Tough cookery. Nature 389, 675–677 (1997). https://doi.org/10.1038/39475

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