Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics
Abstract
A high-strength, fracture-resistant silicon nitride ceramic material that includes about 5 to about 75 wt-% of elongated reinforcing grains of beta-silicon nitride, about 20 to about 95 wt-% of fine grains of beta-silicon nitride, wherein the fine grains have a major axis of less than about 1 micron; and about 1 to about 15 wt-% of an amorphous intergranular phase comprising Si, N, O, a rare earth element and a secondary densification element. The elongated reinforcing grains have an aspect ratio of 2:1 or greater and a major axis measuring about 1 micron or greater. The elongated reinforcing grains are essentially isotropically oriented within the ceramic microstructure. The silicon nitride ceramic exhibits a room temperature flexure strength of 1,000 MPa or greater and a fracture toughness of 9 MPa-m.sup.(1/2) or greater. The silicon nitride ceramic exhibits a peak strength of 800 MPa or greater at 1200 degrees C. Also included are methods of making silicon nitride ceramic materials which exhibit the described high flexure strength and fracture-resistant values.
- Inventors:
-
- Oak Ridge, TN
- Issue Date:
- Research Org.:
- UT-Battelle LLC/ORNL, Oak Ridge, TN (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1018720
- Patent Number(s):
- 7968484
- Application Number:
- US Patent Application 11/851,540
- Assignee:
- UT-Battelle, LLC (Oak Ridge, TN)
- Patent Classifications (CPCs):
-
C - CHEMISTRY C04 - CEMENTS C04B - LIME, MAGNESIA
- DOE Contract Number:
- AC05-00OR22725
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE
Citation Formats
Becher, Paul F, and Lin, Hua-Tay. Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics. United States: N. p., 2011.
Web.
Becher, Paul F, & Lin, Hua-Tay. Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics. United States.
Becher, Paul F, and Lin, Hua-Tay. Tue .
"Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics". United States. https://www.osti.gov/servlets/purl/1018720.
@article{osti_1018720,
title = {Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics},
author = {Becher, Paul F and Lin, Hua-Tay},
abstractNote = {A high-strength, fracture-resistant silicon nitride ceramic material that includes about 5 to about 75 wt-% of elongated reinforcing grains of beta-silicon nitride, about 20 to about 95 wt-% of fine grains of beta-silicon nitride, wherein the fine grains have a major axis of less than about 1 micron; and about 1 to about 15 wt-% of an amorphous intergranular phase comprising Si, N, O, a rare earth element and a secondary densification element. The elongated reinforcing grains have an aspect ratio of 2:1 or greater and a major axis measuring about 1 micron or greater. The elongated reinforcing grains are essentially isotropically oriented within the ceramic microstructure. The silicon nitride ceramic exhibits a room temperature flexure strength of 1,000 MPa or greater and a fracture toughness of 9 MPa-m.sup.(1/2) or greater. The silicon nitride ceramic exhibits a peak strength of 800 MPa or greater at 1200 degrees C. Also included are methods of making silicon nitride ceramic materials which exhibit the described high flexure strength and fracture-resistant values.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {6}
}
Works referenced in this record:
Temperature-Dependent Viscosity of SiREAl-Based Glasses as a Function of N:O and RE:Al Ratios (RE = La, Gd, Y, and Lu)
journal, July 2004
- Becher, Paul F.; Ferber, M. K.
- Journal of the American Ceramic Society, Vol. 87, Issue 7