EVALUATION OF PS200 PLASMA COATING IN AN AIR-COOLED ROTARY ENGINE.

RECENT TESTS HAVE INDICATED THAT A THERMAL BARRIER COATING ON AN AIR-COOLED ROTARY ENGINE SIDE HOUSING RESULTS IN SURFACE TEMPERATURES BEYOND THE CAPABILITY OF CONVENTIONAL HYDROCARBON LUBRICANTS. PS200 IS A PLASMA APPLIED COATING OF CHROMIUM CARBIDE WITH SILVER AND A FLUORIDE EUTECTIC FOR HIGH TEMPERATURE LUBRICITY. IT WAS DEVELOPED BY HAROLD SLINEY OF NASA LEWIS AS AN UNLUBRICATED WEAR COATING FOR STIRLING ENGINES. IT IS UNIQUELY SUITED AS A WEAR/LUBRICANTCOATING FOR APPLICATION OVER A THERMAL BARRIER COATING, TO PERMIT ENGINE OPERATION WITHOUT THE NEED OF EXTERNAL LUBRICATION. A SUCCESSFUL THERMAL BARRIER COATING WILL REDUCE ENGINE HEAT REJECTION, IMPROVING THERMAL EFFICIENCY AND REDUCING COOLING AIR FLOW REQUIREMENTS. IT WILL ALSO ENHANCE THE OPERATION OF THE DIRECT INJECTED, MULTI-FUEL VERSION OF THE ENGINE WHEN IT IS FULLY DEVELOPED. THE SUCCESS OF THIS COATING EVALUATION ON A SIDE HOUSING WILL LEAD TO THE INSULATION OF THE ENTIRE COMBUSTION CHAMBEROF THE ROTARY ENGINE, COATING THE ROTOR HOUSING WITH THE SAME THERMAL BARRIER COATING COMBINATION.