Effect of AlN and Al2O3 Additions on the Phase Relationships and Morphology of SiC. Part I. Compositions and Properties
X-ray diffraction was utilized to follow the transformation from β-SiC (3C) to the various α-SiC polytypes in the presence of AlN and Al2O3 additives after hot pressing from 1700 to 2100⁰C. The 2H- and 6H-polytypes of α-SiC were the predominate polytypes with additions of only AlN or Al2O3, respectively. The amount of 2H- and 6H-polytypes, and subsequently the microstructural morphology of the SiC materials, were found to be controlled by varying the amount of AlN and Al2O3. Improvements in fracture toughness to approx. 9 MPa-√m were achieved with flexural strengths ranging from 600 to 900 MPa. These results suggest that accurate control of the polytypic make-up of SiC-based materials, along with their mechanical properties, can be achieved through AlN and Al2O3 additions.
G. Hilmas and T. Tien, "Effect of AlN and Al2O3 Additions on the Phase Relationships and Morphology of SiC. Part I. Compositions and Properties," Journal of Materials Science, vol. 34, no. 22, pp. 5605-5612, Kluwer Academic Publishers, Nov 1999.
The definitive version is available at http://dx.doi.org/10.1023/A:1004793302482
Materials Science and Engineering
Keywords and Phrases
Alumina; Aluminum compounds; Bending strength; Crystal microstructure; Fracture toughness; Hot pressing; Mechanical properties; Morphology; Phase transitions; Temperature measurement; X ray diffraction analysis; Aluminum nitride; Polytypes; Silicon carbide
International Standard Serial Number (ISSN)
Article - Journal
© 1999 Kluwer Academic Publishers, All rights reserved.