Browse by author
Lookup NU author(s): Dr Zafer Tatli, Emeritus Professor Derek Thompson
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
Silicon nitride can easily be hot-pressed with small additions of metal oxide to give a product with high strength and zero porosity but the disadvantage of hot-pressing is that it is an expensive process limited to the formation of fairly simple shapes and small batches. The present work has therefore focused on preparing MgO densified samples of silicon nitride by the much cheaper and more versatile technique of pressureless sintering. Thin layers of oxides, corresponding to additions of up to 5 w/o MgO have been deposited on the surface of grains of a commercial silicon nitride powder using alcoholic solutions containing appropriate amounts of the metal alkoxide. The resulting powders have been densified by pressureless sintering technique, and their sintering characteristics identified in comparison with equivalent materials produced by adding the oxide in particulate form In every case, a better sintering performance was observed at lower temperatures for the oxide-coated materials, with fully dense pressureless-sintered materials being obtained at temperatures as low as 1525°C. The final microstructure was more uniform, and the 100- 150°C reduction in sintering temperature resulted in considerably reduced weight losses, making it possible to dispense with the use of powder beds. By choosing a suitable composition of the powder bed it is possible to control weight loss by volatilisation of MgO.
Author(s): Tatli Z, Thompson DP
Editor(s): Saritas S., Uslan I., Usta Y.
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 3rd International Powder Metallurgy Conference
Year of Conference: 2002
Pages: 148-157
Publisher: Gazi University
Library holdings: Search Newcastle University Library for this item
ISBN: 9759246309
