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 https://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.
01 Nov 1999