ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Oxynitirde glasses are found at triple point junctions and as intergranular films insilicon nitride based ceramics. The glass chemistry, particularly the content ofmodifyer,usually Y or a rare earth (RE) ion, and the volume fractions of these oxynitride glassphases within the ceramic control the properties of silicon nitride, in particular, creep at hightemperature. It is known that, as nitrogen substitutes for oxygen in silicate and aluminosilicateglass networks, increases are observed in glass transition and softening temperatures,viscosities (by two to three orders of magnitude), elastic moduli and microhardness. Ifchanges are made to the RE:Si:Al ratios or different rare earth cation are substituted,properties such as viscosity can be increased by a further two to three orders of magnitude.These effects have implications for the high temperature properties of silicon nitride basedceramics, especially creep resistance. This paper provides an overview of oxynitride glassesand outlines the effect of composition on properties such as glass transition temperature andviscosity and discusses the effects on high temperature behaviour of silicon nitride ceramics
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.317-318.419.pdf
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