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- Title
Optimization of Phase Purity of β′-Sialon Ceramics Produced from Silazanes and Nano-Sized Alumina.
- Authors
Parcianello, Giulio; Bernardo, Enrico; Colombo, Paolo; Gauckler, L.
- Abstract
The use of preceramic polymers in the synthesis of Sialon ceramics has been scarcely discussed in the literature. In this article we report the production of virtually phase-pure β′-Sialon ceramics from a mixture of commercially available polysilazanes and γ- Al2 O3 nanopowder, pyrolized in N2 atmosphere in the 1300°C-1600°C range. This approach combines the advantage of embedding nano-sized fillers in preceramic polymers, in terms of their reactivity towards the Si- N based ceramic pyrolysis residue, with the complex interactions with residual carbon, also present as a secondary phase in the same ceramic residue. Starting from a polymer ( PSZ20) yielding a SiCN amorphous ceramic after pyrolysis, the Sialon phase purity is greatly affected by the residual C content: for an optimized polymer/filler ratio ( PSZ20/ Al2 O3 = 2), β′-Sialon can be produced possesing only small quantities of quasi-amorphous SiC as a secondary phase. Additional improvements based on the partial replacement of PSZ20 with a polymer ( PHPS) not containing C in the backbone, lead to the production of pure nanocrystalline β′-Sialon powders (average grain size of 100-200 nm).
- Publication
Journal of the American Ceramic Society, 2012, Vol 95, Issue 7, p2148
- ISSN
0002-7820
- Publication type
Article
- DOI
10.1111/j.1551-2916.2012.05179.x