Accession Number:

ADA207907

Title:

Explanatory Research on the Protection of Carbon-Carbon Composites against Oxidation at Very High Temperatures (>3000 Deg F)with Engel-Brewer and Other Intermetallic Compounds

Descriptive Note:

Final rept.

Corporate Author:

OHIO STATE UNIV COLUMBUS DEPT OF METALLURGICAL ENGINEERING AND MATERIALS SCIENCE

Personal Author(s):

Report Date:

1988-06-01

Pagination or Media Count:

204.0

Abstract:

Iridium-based coatings have been proposed for the protection of carboncarbon composites against oxidation at temperatures greater than 1600 C. However, Ir exposed to an oxidizing atmosphere at such high temperatures reacts with oxygen to form volatile oxides. Alloying Ir with a reactive element that forms a protective scale has been proposed as a method to prevent the evaporation of Iridium base coatings. Hafnium and Zr were suggested as possible alloying elements. Investigations of the Ir-Hf and the Pt-Zr systems, however, have shown that Hf and Zr are only moderately protective. In both systems the reactive element, Hf and Zr, did not form a highly protective oxide scale. Aluminum is another possible alloying addition for the prevention of evaporation of the noble metal suboxides. Samples of CC composite would be coated with HfC and then a layer of Iridium would be applied. It has been demonstrated that we can grow an adherent layer of Ir3Hf between these coatings. The surface of the Ir would be impregnated with A1 and Cr. Keywords Oxidation Hafnium Carbon carbon composits.

Subject Categories:

  • Coatings, Colorants and Finishes
  • Laminates and Composite Materials

Distribution Statement:

APPROVED FOR PUBLIC RELEASE