Structural dense silicon nitrides

Silicon nitride is receiving considerable attention as a structural ceramic, which requires a fully dense material, but it is also of interest to consider whether it could be prepared in high surface area forms. Our work in this direction has led to a synthesis of a high surface area silicon oxynitride. We summarise here the synthetic work and then report data on the stability of the surface. 

Although, in structural materials, the pores are generally beheved to cause a deterioration in mechanical reliability, this is not always true. Rather, the pores may cause an improved or even unique mechanical performance of the material which cannot be attained in the dense counterpart, especially when the porous microstructure is carefully tailored. Two examples of porous silicon nitrides are described in the... 

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