Effect of different rare earth cations on the densification behaviour of oxygen rich α-SiAlON composition
| Autor: | Siddhartha Bandyopadhyay, Michael J. Hoffmann, Günter Petzow |
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| Rok vydání: | 1999 |
| Předmět: |
Sialon
Materials science Ionic radius Process Chemistry and Technology Aluminate Metallurgy Sintering Melilite engineering.material Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography chemistry.chemical_compound chemistry Phase (matter) Volume fraction Vickers hardness test Materials Chemistry Ceramics and Composites engineering |
| Zdroj: | Ceramics International. 25:207-213 |
| ISSN: | 0272-8842 |
| Popis: | Five different stabilizing cations (Y, Yb, Dy, Sm, Nd) were investigated on an α-SiAlON composition, deliberately shifted to the Al 2 O 3 rich area corresponding to M 0.445 Si 9.998 Al 2.003 O 0.668 N1 5.333, with respect to the reaction sequences, densification behaviour and mechanical properties. The analysis of the reaction sequences show that the formation of α-SiAlON involves the intermediate formation of aluminate, garnet, melilite and a nitrogen rich liquid containing the respective cation. The sintering rate is influenced by volume fraction of the garnet and melilite phase which varies for different cations. Dy 2 O 3 shows the best densification behaviour which is followed by Sm 2 O 3 and Nd 2 O 3 . The fracture toughness for all are comparable while the hardness value seems to decrease with the increasing ionic size of the cations due to the lower proportions of α-SiAlON phase. The present composition favours the removal of melilite from the as cooled product as well as good densification. |
| Databáze: | OpenAIRE |
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