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Tuesday, October 19, 2004 - 2:30 PM
ATT 2.2

Low Pressure Plasma Sprayed Overlay Coatings for GRCop-84 Combustion Chamber Liners for Reusable Launch Vehicles

S. V. Raj, B. A. Lerch, C. A. Barrett, NASA Glenn Research Center, Cleveland, OH; L. J. Ghosn, Ohio Aerospace Institute, Cleveland, OH; R. C. Robinson, QSS, Inc., Cleveland, OH; G. Thom, Plasma Processes, Inc., Huntsville, AL

An advanced Cu-8(at.%)Cr-4%Nb alloy developed at NASA’s Glenn Research Center, and designated as GRCop-84, is currently being considered for use as liners in combustor chambers and nozzle ramps in NASA’s future generations of reusable launch vehicles (RLVs). However, past experience has shown that unprotected copper alloys undergo an environmental attack called “blanching” in rocket engines using liquid hydrogen as fuel and liquid oxygen as the oxidizer. Potential for sulfidation attack of the liners in hydrocarbon-fueled engines is also of concern. As a result, protective overlay coatings alloys are being developed for GRCop-84. The development of this coatings technology has involved a combination of modeling, alloy development, characterization, and process optimization. Coatings have been low pressure plasma sprayed on GRCop-84 substrates of various geometries and shapes. Microstructural, mechanical property data and thermophysical results on the coated substrates are presented and discussed.

Summary: The development of coatings technology for a state-of-the art copper alloy (GRCop-84) has involved a combination of modeling, alloy development, characterization and process optimization. Microstructural, mechanical property data and thermophysical results on the low pressure plasma sprayed coated substrates are presented and discussed.