Mechanical and Thermal Properties of AlN-BN-SiC Ceramics
Mechanical and thermal properties were characterized for two AlN:BN:SiC composite ceramics produced from BN with different particle sizes. The ceramics were hot pressed at temperatures from 1950 to 2100 °C to not, vert, similar97% relative density. For both materials, the matrix (90:10 vol% SiC:AlN) had a grain size of not, vert, similar0.4 μm, and the BN grains (10 vol%) were crystallographically aligned. Microhardness values were between 20 and 22 GPa, while fracture toughness values were between 2.5 and 3.1 MPa m1/2. Other properties were found to be dependent on testing direction. Elastic moduli were between 260 and 300 GPa and strengths were not, vert, similar630 MPa for small particle BN additions. Thermal conductivity was calculated to be between 25 and 37 W/m K at room temperature and 17 and 25 W/m K at 900 °C. The low values compared to traditional SiC ceramics were attributed to AlN-SiC solid solution formation and sub-micron matrix grain sizes.
A. A. Buchheit et al., "Mechanical and Thermal Properties of AlN-BN-SiC Ceramics," Materials Science and Engineering: A, Elsevier, Oct 2008.
The definitive version is available at http://dx.doi.org/10.1016/j.msea.2008.05.051
Materials Science and Engineering
Keywords and Phrases
Hot Pressing; Mechanical Properties; Thermal Properties; Aluminum nitride; Boron nitride; Silicon carbide
Article - Conference proceedings
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