CODEPOSITION OF METALS FOR OXIDATION PROTECTION ABOVE 2200 DEGREES CENTIGRADE

PLATINUM GROUP METAL (PGM) COATINGS HAVE BEEN SHOWN TO PROVIDE OXIDATION PROTECTION FOR ROCKET ENGINE COMPONENTS OPERATING TO 2200 DEGREES CENTIGRADE. THESE COATINGS ARE NOT INERT TO OXYGEN; RATHER, THEY FORM VOLATILE OXIDES WHICHERODE AT A MEASURABLE RATE. PLATINUM, RHODIUM, AND IRIDIUM FORM COMPOUNDS WITH ZIRCONIUM AND HAFNIUM. THESE SO-CALLED ENGEL-BREWER COMPOUNDS ARE OF GREAT INTEREST BECAUSE THEY ARE VERY STABLE, WITH MELTING POINTS HIGHER THAN THOSE OF EITHER CONSTITUENT. FURTHERMORE, ZIRCONIUM AND HAFNIUM CAN BE FORMED BY CHEMICAL VAPOR DEPOSITION (CVD) FROM BETA-DIKETONE COMPOUNDS, WHICH HAVE DEPOSITION PARAMETERS SIMILAR TO THOSE EMPLOYED FOR DEPOSITING PLATINUM GROUP METALS. CODEPOSITION IS THUS POSSIBLE, WHICH WILL PRODUCE COATINGS OF UNIFORM CONSTITUENCY. IN THIS PHASE I PROGRAM, ULTRAMET PROPOSES TO DEMONSTRATE THE FEASIBILITY OF FORMING ENGEL-BREWER COMPOUND COATINGS IN THIS MANNER AND TEST FOR OXIDATION RESISTANCE TO 2400 DEGREES CENTIGRADE.