Chapter 26. Stability of a Sapphire/Yttrium Aluminum Garnet Composite System
- John B. Wachtman Jr.
Published Online: 26 MAR 2008
Copyright © 1989 The American Ceramic Society, Inc.
A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8
How to Cite
Matson, L. E., Hay, R. S. and Mah, T. (1989) Stability of a Sapphire/Yttrium Aluminum Garnet Composite System, in A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310557.ch26
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1989
Print ISBN: 9780470374863
Online ISBN: 9780470310557
- chemical vapor deposition;
- fiber-reinforced ceramic composites;
- chemical vapor infiltration;
- high fracture toughness;
- carbon-carbon composites
Sapphire filaments were vacuum hot-pressed at 1500°–1650°C in a yttrium aluminum garnet (YAG) powder matrix. The YAG powders were derived from alkoxide precursors. A fully dense composite with a YAG grain size of 1-5 pun was obtained. Some samples were heat-treated further for 75 h at 1400°C in air. No evidence of second-phases along interfaces, or of chemical reaction between the sapphire and YAG, was observed by optical microscopy, electron microprobe, or analytical TEM. However, triple junction equilibrium between YAG grain boundaries and YAG/sapphire interphase boundaries resulted in a cusped YAG/sapphire interface. Triple junction angles indicate that YAG grain boundaries and YAG/alumina interphase boundaries have nearly equal interface energies. Lack of a smooth YAG/sapphire interface is anticipated to cause poor pull-out properties.