HIGH TEMPERATURE OXIDATION RESISTANT COATINGS

IN ORDER TO ACHIEVE INCREASED EFFICIENCY, LIFE, AND PERFORMANCE, ROCKET ENGINES REQUIRE OPERATION AT HIGHER AND HIGHER TEMPERATURES. IN ORDER TO OBTAIN SUFFICIENT STRENGTH AT THESE TEMPERATURES, THE REFRACTORY METALS SUCH AS MOLYBDENUM, TUNGSTEN, TANTALUM, NIOBIUM, AND RHENIUM MUST BE USED TO FABRICATE THE PARTS WHICH WILL BE EXPOSED TO THESE TEMPERATURES. THESE METALS AND THEIR STRUCTURALLY IMPORTANT ALLOYS HAVE NOTORIOUSLY POOR RESISTANCE TO OXIDATION IN THE TEMPERATURE RANGE WHERE THEIR STRENGTH CHARACTERISTICS ARE VITALLY NEEDED. PROTECTION, IN THE FORM OF COATINGS, FROM THE OXIDIZING ENVIRONMENT IS CRUCIAL FOR SUCCESSFUL OPERATION. CURRENT COATING TECHNOLOGY IS NOT SUFFICIENT TO ACHIEVE SATISFACTORYOPERATION. NEW OXIDATION RESISTANT COATING MATERIALS AND PROCESSES MUST BE DEVELOPED WHICH WILL PERMIT OPERATION IN THE 500C TO 2000C TEMPERATURE RANGE. HAFNIUM OXIDE AMD ZIRCONIUM OXIDE OFFER TWO POTENTIAL CANDIDATES FOR OXIDATION RESISTANT COATING MATERIALS. ULTRAMET PROPOSES TO DEVELOP THE TECHNOLOGY REQUIRED TO CHEMICALLY VAPOR DEPOSIT DENSE, ADHERENT COATINGS OF HAFNIUM OXIDE AND ZIRCONIUM OXIDE AND TO DETERMINE THEIR OXIDATION PROTECTIVE TEMPERATURE RANGE. ULTRAMET HAS HAD EXPERIENCE CHEMICALLY VAPOR DEPOSITING BOTH MATERIALS AND INITIAL TESTS ON HAFNIUM OXIDE ARE VERY ENCOURAGING.