Alumina-γ-aluminum oxynitride composites from alumina nitrided by ammonia

✍ Scribed by J. Sappei; D. Goeuriot; F. Thevenot; Y. Laurent; J. Guyader; P. L'Haridon

• Book ID: 103973628
• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 573 KB
• Volume: 8
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/0955-2219(91)90103-7

✦ Synopsis

By reaction between transition (7) aluminas .from boehmite and ammonia (T.~ IO00-1100°C), up to l%wt nitrogen can be .fixed in the form of a yaluminum oxynitride layer on 7-Al203 sulface grains. This layer delays the polymorphic transjormation of 7-into ~°AI20 3. For higher nitrogen contents, aluminum nitride appears. An application can be the preparation of partially nitrided Al20 3 powder in Y-AION and/or AIN, that can lead to 7-AION single phase or AlzO3-7-AION composites. Such composites, obtained by 7-A1203 partially nitrided in AION, present 7-AION along grain boundaries; that microstructure is efficient in increasing the composite wear resistance.