Coating carbon substrates with refractory metal carbides

Claim 1

A PROCESS FOR PROVIDING CARBON SUBSTRATES WITH AN ADHERENT COATING PREDOMINANTLY IN THE FORM OF A CARBIDE SELECTED FROM THE GROUP CONSISTING OF HAFNIUM CARBIDE, TANTALUM CARBIDE, TITANIUM CARBIDE, ZIRCONIUM CARBIDE AND COLUMBIUM CARBIDE, SAID PROCESS COMPRISING (1) INTIMATELY CONTACTING A CARBON SUBSTRATE WITH A MIXTURE OF CARBIDE CARRIER MATERIAL AND A SOURCE OF SILICON SAID CARBIDE CARRIER MATERIAL BEING SELECTED FROM THE GROUP CONSISTING OF SILICON CARBIDE, TITANIUM CARBIDE, ZIRCONIUM CARBIDE, HAFNIUM CARBIDE AND TANTALUM CARBIDE AND SAID SOURCE OF SILICON BEING SELECTED FROM THE GROUP CONSISTING OF SILICON AND SILICON OXIDE (2) HEATING THE MIXTURE AND SUBSTRATE TO AN ELEVATED TEMPERATURE TO PROVIDE THE SUBSTRATE WITH A COATING OF SILICON CARBIDE (3) REMOVING THE SILICON CARBIDE COATED CARBON SUBSTRATE THUS OBTAINED FROM THE AFOREMENTIONED MIXTURE AND INTIMATELY CONTACTING SAID SUBSTRATE WITH A SECOND MIXTURE OF CARBIDE CARRIER MATERIAL WITH A METAL SELECTED FROM THE GROUP CONSISTING OF HF, TI, ZR, TA AND CB, SAID CARBIDE CARRIER MATERIAL IN SAID SECOND MIXTURE BEING SELECTED FROM THE GROUP CONSISTING TITANIUM CARBIDE, ZIRCONIUM CARBIDE, HAFNIUM CARBIDE AND TANTALUM CARBIDE AND (4) HEATING THE LAST MENTIONED MIXTURE AND SILICON CARBIDE COATED CARBON SUBSTRATE TO AN ELEVATED TEMPERATURE TO CAUSE REACTION OF THE SELECTED METAL AND THE SILICON CARBIDE COATING AND THE FORMATION OF CARBIDE OF THE SELECTED METAL.