NASA 1996 SBIR Phase I

PROJECT TITLE : Novel, Low -Temperature Ir-Re Coating for Oxidation Resistant Carbon Fibers

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

The future use of CMC's and MMC's with carbon fiber reinforcement is essential in enabling NASA and DoD to achieve the advanced propulsion goals set out by IHPRPT. The major drawback with their use as reinforcement for CMC's and MMC's, is their poor oxidation resistance at temperatures above approximately 500¡C resulting in a rapid loss of fiber strength. Ceramics Composites Inc. CCI proposes a novel low temperature chemical vapor infiltration/deposition (CVI/CVD) process to continuously coat carbon fibers with a thin nano-crystalline layer of Ir-Re. The low temperature CVD process results in a ductile nano-crystalline codeposit of Ir-Re which adheres well to the carbon substrate and shows excellent oxidation resistance up to 2000¡C.

Rocketdyne have expressed an interest in oxidation resistant carbon fibers and would like to work with CCI to fabricate and evaluate these composite thrusters. The Phase II effort will focus on fabricating a small 100lbf thruster based on a Rocketdyne design with the Ir-Re coated fibers. The braided thruster will be densified at CCI with a ceramic matrix (HfC-TaC). Rocketdyne will test the completed thruster and the data will be used to demonstrate extended life for the Ir-Re coated carbon fibers.

This CVD technology to codeposit oxidation resistant Ir alloy coatings, can be used to provide improved high temperature oxidation resistance for a wide range of applications. The Phase I effort develops the coating for fibers which can be braided into composite structures, but these coatings can also be used to provide protection to structures such as C/C composites or monolithic Re thrusters.

Ceramic Composites, Inc.
1110 Benfield Blvd.
Millersville, MD 21108