Method of forming protective coatings for metallic surfaces

Claim 1

A PROCESS FOR PRODUCING AN OXYGEN-FREE NON-EMISSIVE GRID STRUCTURE CONSISTING IN INTIMATE COMBINATION OF A REFRACTORY METAL CORE, A NON-EMISSIVE MATERIAL AND AN INTER-METALLIC CARBIDE BARRIER LAYER DISPOSED THEREBETWEEN, THE STEPS COMPRISING APPLYING TO A CORE OF A PREVIOUSLY FIRED REFRACTORY MEAL CHOSEN FROM THE CLASS CONSISTING OF TANTALUM, COLUMBIUM, MOLYBDENUM, TUNGSTEN AND ALLOYS, IN WHICH AT LEAST ONE OF SAID METALS IS THE PREDOMINANT COMPONENT, A LAYER OF A HYDRIDE OF A SECOND RREFRACTORY METAL CHOSEN FROM THE CLASS CONSISTING OF THE HYDRIDES OF ZIRCONIUM, TITANIUM, AND SILICON, ELEVATING THE TEMPERATURE OF THE COATED CORE TO BETWEEN ABOUT 1700* C. AND ABOUT 2000* C. TO DECOMPOSE THE HYDRIDE, CONVERT IT INTO A SINTERED REFRACTORY COATING OF SAID SECOND METAL AND CAUSE SAID SINTER REFRACRORY COATING TO AT LEAST PARTIALLY REACT WITH THE SURFACE STRATA OF SAID BASE METAL TO FORM THEREWITH AN INTER-METALLIC COMPOUND, APPLYING A LAYER OF CARBON ON SAID SINTERED COATING ELEVATING THE CORE TEMPERATURE TO BETWEEN ABOUT 1700* C. AND ABOUT 2000* C. TO FORM AN INTER-METALLIC CARBIDE WITH SAID INTER-METALLIC COMPOUND THEREBY PRODUCING A BARRIER LAYER TO PREVENT MIGRATION THERETHROUGH APPLYING A LAYER OF A NON-EMISSIVE MATERIAL ON SAID BARRIER LAYER AND HEATING THE RESULTANT STRUCTURE TO OBTAIN AN INTIMATE BOND BETWEEN THE CONTACTING SURFACES OF SAID NON-EMISSIVE MATERIAL AND SAID BARRIER LAYER.