Ultrafine Microstructure Composites Prepared by Chemical Vapor Deposition
Abstract
In recent years material requirements have become more strict and sophisticated for many novel applications such as space vehicles, ultrasonic jets, ceramic heat engines, high performance cutting tools, etc. It is of great interest to prepare advanced ceramics that possess high temperature stability and strength. A major difficulty exists, however, as the traditional brittleness of ceramics often causes catastrophic failures, thus, limiting their wide usage. Dispersed phase ceramic composites appear to be one solution to this problem. The composites usually possess superior mechanical properties (e.g., fracture toughness, strength, resistance to wear and erosion, hardness, etc.) compared to those of single phase ceramics. The performance of dispersed phase ceramic composites is strongly related to their microstructures. Chemical vapor deposition (CVD) offers an alternative avenue of preparing ceramic composite in the form of coatings by either simultaneous deposition of multiple phases (i.e., codeposition) or by alternately depositing several phases. The major advantage of preparing phase ceramic composites by CVD is that mechanical as well as chemical, electrical, optical and thermal properties of the composites can be favorably tailored by controlling their composition and microstructure. The desired microstructure can be achieved by optimization of CVD process variables such as temperature, pressure, reagent concentration, substrate type, reactor geometry, etc.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA219650
Entities
People
- Andrew J. Green
- Douglas J. Twait
- Garth B. Freeman
- Geoving J. Gerard
- John A. Hanigofsky
- John R. Thompson
- Pradeep K. Agrawal
- Thomas S. Moss Iii
- W. J. Lackey
- Woo Y. Lee
Organizations
- Georgia Tech Research Corporation