Blanching resistant coating for copper alloy rocket engine main chamber lining

Copper alloy rocket engine combustion chamber linings have been found to deteriorate when exposed to cyclic reducing/oxidizing (redox) environments which are a consequence of the combustion process. This deterioration, known as blanching, can be characterized by increased roughness and bum through sites in the wall of the combustion chamber lining and can seriously reduce the operational lifetime of the combustion chamber. The blanching problem can be significantly reduced by depositing a thin layer of Cu-30v/oCr (a copper matrix with 30+/-10 volume percent of chromium) on the inside wall of the combustion chamber. The microstructure of the Cu-30v/oCr coating consists of finely distributed chromium (Cr) particles in a copper (Cu) matrix. When exposed to an oxidizing environment at high temperatures, the coating forms a protective chromium scale which is stable in hydrogen atmospheres (e.g., substantially unreduced by high pressure hydrogen). The Cu-30v/oCr coating can be applied, for example, using low temperature arc vapor deposition or low pressure plasma spray techniques.