Vacuum heat treatment of LiAlO2 densified silicon nitride ceramics
Küçük Resim Yok
Tarih
2006
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Sci Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The aim of the present work has been to produce high-dense Si3N4 ceramics by a cheaper pressureless sintering method and then to attain vacuum heat treatment to remove residual grain boundary glass in gaseous form. LiAlO2, was used as a sintering additive rather than using Li2O, since its grain boundary glass is not stable above 1200 degrees C. LiAlO2 was synthesised from 42% Li2CO3 and 58% Al2O3 powder mix reacting together at 1450 degrees C for 3 h in a muffle furnace. X-ray analysis showed that 95% LiAlO2 was obtained. LiAlO2, was milled and added to silicon nitride powder as a sintering additive. Hot-pressing and pressureless sintering of LiAlO2 containing Si3N4 compacts were carried out at temperatures between 1450-1750 degrees C. The sintered samples were vacuum heat-treated at elevated temperatures under high vacuum to remove intergranular glass and to increase refractoriness Of Si3N4 ceramics. Scanning electron microscope images and weight loss results showed that Li in grain boundary glass (Li-Al-Si-O-N) was successfully volatilised, and oxidation resistance of the sintered samples was increased. (C) 2005 Elsevier Ltd. All rights reserved.
Açıklama
Anahtar Kelimeler
silicon nitride LiAlO2, hot-pressing, pressureless sintering, vacuum heat treatment
Kaynak
Materials & Design
WoS Q Değeri
Q3
Scopus Q Değeri
Cilt
27
Sayı
10
