Method of preparing oxidation resistant materials and structures

Claim 1

The method of preparing oxidation resistant matrix structures alloyed at least in portions thereof with chromium and aluminum, comprising the steps of: providing an iron-base alloy matrix assembly, providing a mixture of aluminum source material and chromium source material, the aluminum source material being selected from the group consisting of Al-Fe alloys, Al-Cr alloys, and mixtures thereof the chromium source material being selected from the group consisting of Cr-Fe alloys, Al-Cr alloys, Cr and mixtures thereof at various surfaces of the matrix assembly, and heating the assembly in an atmosphere of H2 and HF to an elevated temperature for a time sufficient to effect the diffusion of Al and Cr into the iron-base alloy.

Claim 2

The method of preparing oxidation resistant matrix structures alloyed at least in portions thereof with chromium and aluminum, comprising the steps of: providing an iron-base alloy matrix assembly, providing a mixture of aluminum source material and chromium source material, the aluminum source material being selected from the group consisting of Al-Fe alloys, Al-Cr alloys, and mixtures thereof the chromium source material being selected from the group consisting of Cr-Fe alloys, Al-Cr alloys, Cr and mixtures thereof at various surfaces of the matrix assembly, and heating the assembly in an atmosphere of H2 and HF to an elevated temperature for a time sufficient to effect the diffusion of Al and Cr into the iron-base alloy.

Claim 8

THE METHOD OF SIMULTANEOUSLY DIFFUSION ALLOYING AND BONDING A MATRIX ASSEMBLY MADE UP FOR THE MOST PART OF LOW CARBON STEEL FOIL BY THE CODIFFUSION OF ALLUMINUM AND CHROMIUM INTO THE ASSEMBLED STEEL PARTS COMPRISING THE STEPS OF: DIPPING THE ASSEMBLY INTO A SLURRY COMPRISED OF ABOUT 1:1 AL-FE AND CR POWDERS PRESENT IN ABOUT 4:5 RATIO AND SUSPENDED IN A VISCOUS BINDER VEHICLE; REMOVING EXCESS SLURRY MATERIAL FROM THE ASSEMBLY AFTER WITHDRAWING IT FROM THE SLURRY; PLACING THE ASSEMBLY IN A SEALED DIFFUSION CONTAINER; UURGING THE CONTAINER WITH ARGON AT A TEMPERATURE OF ABOUT 700*-800*F. FOR A PERIOD OF ABOUT 2 HOURS TO SUBSTANTIALLY REMOVE THE BINDER VEHICLE; COOLING THE CONTAINER AND CONTENTS; INTRODUCING A MIXED ATMOSPHERE OF H2 AND ABOUT 1% HF BY VOLUME INTO THE CONTAINER; CAUSING THE GAS MIXTURE TO CIRCULATE THROUGH THE CONTAINER FOR ABOUT 15 MINUTES; ESTABLISHING A SUBSTANTIALLY STATIC ATMOSPHERE OF THE MIXTURE IN THE CONTAINER; HEATING THE CONTAINER CINTENTS TO ABOUT 2,00* F AT AN AVERAGE RATE OF ABOUT 400*-500*F. PER HOUR AND HOLDING THE 2,00* F. TEMPERATURE FOR ABOUT 2 HOURS AFTER IT IS REACHED; COOLING THE CONTAINER AND CONTENTS TO ROOM TEMPERATURE, PURGING THE CONTAINER WITH ARGON AT ABOUT 1,00*F. DURING COOL-DOWN, AND FINALLY REMOVING LOOSE RESIDUE REMAINING ON THE CORE.

Claim 9

THE METHOD OF SIMULTANEOUSLY DIFFUSION ALLOYING AND BONDING A MATRIX ASSEMBLY MADE UP FOR THE MOST PART OF LOW CARBON STEEL FOIL BY THE CODIFFUSION OF ALLUMINUM AND CHROMIUM INTO THE ASSEMBLED STEEL PARTS COMPRISING THE STEPS OF: DIPPING THE ASSEMBLY INTO A SLURRY COMPRISED OF ABOUT 1:1 AL-FE AND CR POWDERS PRESENT IN ABOUT 4:5 RATIO AND SUSPENDED IN A VISCOUS BINDER VEHICLE; REMOVING EXCESS SLURRY MATERIAL FROM THE ASSEMBLY AFTER WITHDRAWING IT FROM THE SLURRY; PLACING THE ASSEMBLY IN A SEALED DIFFUSION CONTAINER; UURGING THE CONTAINER WITH ARGON AT A TEMPERATURE OF ABOUT 700*-800*F. FOR A PERIOD OF ABOUT 2 HOURS TO SUBSTANTIALLY REMOVE THE BINDER VEHICLE; COOLING THE CONTAINER AND CONTENTS; INTRODUCING A MIXED ATMOSPHERE OF H2 AND ABOUT 1% HF BY VOLUME INTO THE CONTAINER; CAUSING THE GAS MIXTURE TO CIRCULATE THROUGH THE CONTAINER FOR ABOUT 15 MINUTES; ESTABLISHING A SUBSTANTIALLY STATIC ATMOSPHERE OF THE MIXTURE IN THE CONTAINER; HEATING THE CONTAINER CINTENTS TO ABOUT 2,00* F AT AN AVERAGE RATE OF ABOUT 400*-500*F. PER HOUR AND HOLDING THE 2,00* F. TEMPERATURE FOR ABOUT 2 HOURS AFTER IT IS REACHED; COOLING THE CONTAINER AND CONTENTS TO ROOM TEMPERATURE, PURGING THE CONTAINER WITH ARGON AT ABOUT 1,00*F. DURING COOL-DOWN, AND FINALLY REMOVING LOOSE RESIDUE REMAINING ON THE CORE.

Claim 10

The method of simultaneously diffusing aluminum and chromium comprising: applying a mixture of aluminum source material and chromium source material to a metal surface, the aluminum source being selected from the group consisting of Al-Fe alloys, Al-Cr alloys and mixtures thereof, the chromium source being selected from the group consisting of Cr-Fe alloys, Al-Cr alloys, Cr and mixtures thereof, establishing a diffusion atmosphere predominantly of H2 mixed with minor amounts of HF, heating the surface in the diffusion atmosphere for a time at a temperature sufficient to form fluoride salts of the aluminum and chromium, continuing the heating to reduce the salts and form aluminum and chromium metal at the surface and further continuing the heating to cause the diffusion of the aluminum and chromium into the surface and alloying therewith.

Claim 11

The method of simultaneously diffusing aluminum and chromium comprising: applying a mixture of aluminum source material and chromium source material to a metal surface, the aluminum source being selected from the group consisting of Al-Fe alloys, Al-Cr alloys and mixtures thereof, the chromium source being selected from the group consisting of Cr-Fe alloys, Al-Cr alloys, Cr and mixtures thereof, establishing a diffusion atmosphere predominantly of H2 mixed with minor amounts of HF, heating the surface in the diffusion atmosphere for a time at a temperature sufficient to form fluoride salts of the aluminum and chromium, continuing the heating to reduce the salts and form aluminum and chromium metal at the surface and further continuing the heating to cause the diffusion of the aluminum and chromium into the surface and alloying therewith.