Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7989492 | International Journal of Refractory Metals and Hard Materials | 2018 | 4 Pages |
Abstract
Porous Si3N4 ceramics with a unique interlocking microstructure have been fabricated by pressureless liquid-phase sintering with YbF3 and CaF2 sintering additives at a relatively low temperature (1550â¯Â°C). Phase transition and mass diffusion in the low-temperature sintering process are facilitated by YbF3 and CaF2 producing plenty of liquid phase owing to their extremely low melting points. As the content of YbF3 increases from 8.0â¯wt% to 9.5â¯wt% and the CaF2 decreases from 2.0â¯wt% to 0.5â¯wt%, the conversion rate of the phase transition from α-Si3N4 to β-Si3N4 increases from 71.1% to 81.2% and the largest average aspect ratio of the β-Si3N4 grains reaches 10.05. At the same time, the porosity declines from 40.4% to 34.9% and the flexural strength increases from 168.5â¯MPa to 232.1â¯MPa.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Te Qi, Zhihao Zhao, Yongqiang Sun, Hangyuan Zhao, Xiaolei Li, Huiming Ji,