Stability of Si3N4 and Liquid Phase(s) During Sintering |
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Authors: | C Greskovich S Prochazka |
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Affiliation: | Ceramics Branch, Physical Chemistry Laboratory, General Electric Company, Corporate Research and Development, Schenectady, New York 12301 |
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Abstract: | Advanced sintering techniques for consolidation of Si3N4 powders in the presence of an oxygen-rich liquid phase(s) require high temperatures and usually high nitrogen pressures. A stability diagram is constructed for Si3N4 as a function of the partial pressures of nitrogen (PN2) and silicon (PSi). High PN2 (20 to 100 atm) increases the stability of Si3N4 and the oxygen-rich liquid phase by reducing the PSi and PSi0, respectively. The region of high sinterability is outlined for submicrometer Si3N4 powders containing 7 wt% BeSiN2 and 7 wt% SiO2 as densification aids . |
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