Oxynitride Glasses: Preparation and Properties - Implications for High Temperature Behaviour of Silicon Nitride Ceramics

Author(s):  
Stuart Hampshire ◽  
Michael J. Pomeroy
2006 ◽  
Vol 317-318 ◽  
pp. 419-424 ◽  
Author(s):  
Stuart Hampshire ◽  
Michael J. Pomeroy

Oxynitirde glasses are found at triple point junctions and as intergranular films in silicon nitride based ceramics. The glass chemistry, particularly the content of modifyer,usually Y or a rare earth (RE) ion, and the volume fractions of these oxynitride glass phases within the ceramic control the properties of silicon nitride, in particular, creep at high temperature. It is known that, as nitrogen substitutes for oxygen in silicate and aluminosilicate glass networks, increases are observed in glass transition and softening temperatures, viscosities (by two to three orders of magnitude), elastic moduli and microhardness. If changes 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 based ceramics, especially creep resistance. This paper provides an overview of oxynitride glasses and outlines the effect of composition on properties such as glass transition temperature and viscosity and discusses the effects on high temperature behaviour of silicon nitride ceramics.


1999 ◽  
Vol 65 (633) ◽  
pp. 1132-1139 ◽  
Author(s):  
Kotoji ANDO ◽  
MinCheol CHU ◽  
Yasuyoshi KOBAYASHI ◽  
Feiyuan YAO ◽  
Shigemi SATO

2015 ◽  
Vol 655 ◽  
pp. 11-16 ◽  
Author(s):  
Xing Li Liu ◽  
Meng Meng Peng ◽  
Xiao Shan Ning ◽  
Yosuke Takahashi

To investigate the influence of β-Si3N4 powder on thermal conductivity of silicon nitride, coarse, fine β-Si3N4 powder and various β-Si3N4/α-Si3N4 ratios of starting powders were adopted to fabricate ceramics by spark plasma sintering at 1600°Cand subsequent high-temperature heat treatment at 1900°C with the sintering additives of Y2O3 and MgO. It is found that with more fine β-Si3N4 powder in the starting powder, β-Si3N4 grains exhibit high thermal conductivity, which is partly resulted from the compaction of β-Si3N4 grains.


Sign in / Sign up

Export Citation Format

Share Document