Project Title:

A Coated, Titanium Diboride, Whisker-Toughened, Silicon Carbide Matrix Composite

04.01-1980A
NAS3-25630
A Coated, Titanium Diboride, Whisker-Toughened, Silicon Carbide Matrix
	Composite
Materials and Electrochemical Research
	7960 S Kolb Road
	Tucson, AZ 85706
		J. C. Withers
(602-574-1980)

Abstract:

	Silicon carbide is a very desirable structural ceramic, but state-of-the-art monoliths
lack toughness and reliability. Whisker toughening has not been effective due to
the disappearance of the SiC in the very high temperature consolidation process.
Titanium diboride particles have demonstrated stability in the SiC consolidation
process but do not have a major impact on increasing toughness and lack oxidation
stability above about 1200oC. This project will explore the use of TiB2 whiskers
that should substantially increase toughness and apply a Y2O3 coating to the TiB2
whiskers that should provide oxidation protection above 1400C. The target properties
are 8 MPam toughness and 800 MPa strength above 1400C. Rigorous and unique processing
will be utilized to avoid large particles or agglomerations to produce a theoretical
dense composite with flaw sizes less than the critical size.

Potential Commercial Application:

Potential Commercial Applications: Toughened, oxidation-stable, TiB2 whisker-reinforced
SiC will have applications in aerospace propulsion and power applications, components
for diesel and spark ignition engines, pump seals and parts, nozzles, wear plates,
armor, heat exchangers, etc.