The sintering, microstructural analysis and mechanical properties of two β' MgSiAlON ceramics
Bayliss, Roger W. (1986) The sintering, microstructural analysis and mechanical properties of two β' MgSiAlON ceramics. PhD thesis, University of Warwick.
WRAP_THESIS_Bayliss_1986.pdf - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Official URL: http://webcat.warwick.ac.uk/record=b1448692~S9
This work describes the preparation and the determination of some properties of two magnesium SiAlON ceramics, one with a low substitution level and one with a high substitution level ' phase. Each had a specific amount of spinel as second phase which would form on sintering or after a post-sintering heat-treatment. The work was undertaken because (a) the improvement in the properties of pressureless-sintered yttrium SiAlON ceramics was not as high as anticipated and (b) by applying the knowledge gained with the widely researched yttrium system to the MgSiAlON ceramic system, the properties of the magnesium system may be further improved. Under consideration in this thesis were the sintering of these ceramics and some sintering reactions are proposed. Also discussed is the effect on the microstructure of heating the ceramic in both oxidising and inert atmospheres. Some mechanical properties were determined, including fracture toughness and hardness testing at ambient temperature, and creep testing at upto 1300^oC. It was expected that MgSiAlONs would be easier to sinter due to the lower ternary oxide eutectic temperature and from a sintering view-point the high z materials do offer an alternative system to the yttrium system by being easier to sinter, but the low z material was as difficult to sinter as the yttrium system. Whilst the MgSiAlONs that were produced in this project were generally out-performed, encouraging results were obtained for the high z material in oxidation resistance. Low z material had the highest fracture toughness and hardness - both of which increased by heat-treatment. It is proposed that alterations to this heat-treatment would improve matters and would form a useful area for future work.
|Item Type:||Thesis or Dissertation (PhD)|
|Alternative Title:||The sintering, microstructural analysis and mechanical properties of two beta MgSiAlON ceramics|
|Subjects:||Q Science > QC Physics|
|Library of Congress Subject Headings (LCSH):||Sintering -- Research, Silicon nitride -- Research, Ceramics -- Research, Yttrium -- Research, Metals -- Heat treatment|
|Institution:||University of Warwick|
|Theses Department:||Department of Physics|
|Supervisor(s)/Advisor:||Lewis, M. H. (Mike H.)|
|Sponsors:||Wolfson Trust (WT)|
|Format of File:|
|Extent:||154 leaves : ill., charts|
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