Paper number 301

PERFORMANCES OF Y 2 SIO 5 COATING SYSTEM FOR CARBON/CARBON COMPOSITES

Masayuki Kondo, Yuzuru Ogura, and Tatsuo Morimoto

Advanced Technology Research Center, Mitsubishi Heavy Industries, Ltd., 1-8-1, Sachiura, Kanazawa-ku, Yokohama, 236-8518, Japan

Summary

As an oxidation protection system for carbon/carbon composites beyond, 1800K, authors have proposed Y 2 SiO 5 coating system, which is a multilayer coating system composed of a outer Y 2 SiO 5 layer and a inner SiC layer. This work evaluated the Y 2 SiO 5 coating in re-entry condition, which some space crafts will meet in re-entry. First, erosion test was executed in low oxygen pressure and high velocity gas flow(Mach 3, Ar-20vol%O 2 ) by arc wind tunnel. The Y 2 SiO 5 coating protected a carbon substrate from the erosion test at 2073K for 50 minutes, and the SiC layer was oxidized in active. The Y 2 SiO 5 layer as erosion-tested had adhered to the SiC layer. Next, isothermal oxidation tests were executed in Ar-0.2vol% with an electric furnace. The Y 2 SiO 5 coating performs oxidation protection at 1973K for more than 10 hours, but, adhesion of Y 2 SiO 5 /SiC interface was degraded. This work shows that the Y 2 SiO 5 coating performs oxidation protection above 1973K.

Keywords

yttrium silicate, carbon/carbon composites, oxidation protection, silicon carbide, yttrium silicide, plasma spraying, arc wind tunnel, active oxidation.