Method of brazing porous materials

Claim 1

A METHOD OF BRAZING POROUS MATERIALS, COMPRISING THE STEPS OF PLACING ONE SIDE OF A METAL DAM OF ABOUT .001" TO .010" THICKNESS AND INCLUDING NICKEL IN ITS COMPOSITION IN CONTACT WITH A POROUS METAL; APPOSING A METAL ELEMENT HAVING A SURFACE INCLUDING NICKEL TO THE OTHER SIDE OF SAID DAM, SAID POROUS METTAL AND SAID METAL ELEMENT BEING SELECTED FROM THE GROUP CONSISTING OF STEEL, STAINLESS STEEL, NICKEL BASE ALLOY, COBALT BASE ALLOY, TUNGSTEN, PLATINUM, MOLYBDENUM, COLUMBIUM, AND CHROMIUM; DISPOSING BRAZING ALLOY BETWEEN AND IN CONTACT WITH SAID DAM AND SAID METAL ELEMENT TO FORM A BRAZING ASSSEMBLY; SAID DAM AND SAID BRAZING ALLOY BEING BRAZINLY COMPATIBLE WITH EACH OTHER AND WITH SAID POROUS METAL AND SAID METAL ELEMENT; SAID BRAZING ALLOY HAVING AN INITIAL LIQUIDUS APPRECIABLY HIGHER THAN ITS INITIAL SOLIDUS AND LOWER THAN THE INITIAL LIQUIDUS OF SAID DAM AND CONTAINING IN ITS COMPOSITION AN INTERSTITIAL ELEMENT CAPABLE OF SOLID PHASE DIFFUSION INTO SAID DAM; HEATING SAID ASSEMBLY TO A TEMPERATURE ABOVE SAID BRAZING SOLIDUS AND BELOW SAID BRAZING LIQUIDUS FOR A FIRST PERIOD TO PROGRESSIVELY ALLOY SAID DAM AND SAID METAL ELEMENT WITH SAID BRAZING ALLOY BY SOLID PHASE DIFFUSION DURING SAID FIRST PERIOD TO LOWER THE LIQUIDUS OF SAID DAM TO APPROXIMATELY THE LIQUIDUS OF SAID BRAZING ALLOY TO FORM A REACTION MATERIAL COMBINING SAID DAM AND SAID BRAZING MATERIAL; FURTHER HEATING SAID ASSEMBLY DURING A SECOND PERIOD TO A TEMPERATURE ABOVE THE LIQUIDUS OF SAID REACTION MATERIAL TO UNITE SAID REACTION MATERIAL AND SAID POROUS METAL, AND THUS RAISING THE SOLIDUS OF SAID REACTION MATERIAL DURING SAID SEOND PERIOD ABOVE THE TEMPERATURE OF SAID ASSEMBLY BY FURTHER PROGRESSIVE ALLOYING OF SAID REACTION MATERIAL TO FREEZE SAID REACTION MATERIAL WHILE MAINTAINING SAID SECOND TEMPERATURE TO JOIN SAID POROUS METAL AND SAID METAL ELEMENT BY METALLURGICAL BONDING WITH A MINIMUM OF INFILTRATION OF REACTION MATERIAL INTO THE PORES OF SAID POROUS METAL.