Process for forming unusually strong joints between metals and ceramics by brazing at temperatures that do not exceed 750 degree C

Patent · Tue Nov 11 04:00:00 EST 1986

OSTI ID:6969523

Hammond, J P; David, S A; Woodhouse, J J

A process is described for brazing high melting point iron-containing metals to ceramics at temperatures not greater than 750/sup 0/ C. comprising, in a vacuum: (a) cleaning a surface to be brazed of a ceramic to remove surface oxygen therefrom; (b) coating the cleaned surface of ceramic with a thin layer of an active substrate that is from 0.3 to 1 micron thick; (c) cleaning a surface to be brazed of a high-melting point iron-containing metal to remove any surface carbon therefrom; (d) coating the surface to be brazed of the metal with a thin noncarbon containing metal coating to prevent any carbon contained in the metal from reacting with a brazing alloy; (e) forming an assembly of the ceramic surface and the metal surface in sandwich fashion with a brazing alloy placed therebetween. The brazing alloy has a melting point of less than 750/sup 0/ C., wetting the metal surface and forming a trimetal intermetallic with the active substrate upon brazing; (f) heating the assembly to the melting point of the brazing alloy for a period suitable to permit flow and wetting by the brazing alloy; and (g) cooling the assembly to form a brazed joint between the ceramic surface and the metal surface.

• Assignee: Dept. of Energy, Washington, DC
• Patent Number(s): US 4621761
• OSTI ID: 6969523
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101* -- Metals & Alloys-- Preparation & Fabrication
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
ALLOYS
BRAZED JOINTS
BRAZING
BRAZING ALLOYS
CARBON
CERAMICS
CLEANING
COOLING
DESCALING
ELEMENTS
FABRICATION
IRON
JOINING
JOINTS
MELTING POINTS
METALS
NONMETALS
OXYGEN
PHYSICAL PROPERTIES
SUBSTRATES
SURFACE FINISHING
SURFACE TREATMENTS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
TRANSITION TEMPERATURE
VACUUM SYSTEMS
VERY HIGH TEMPERATURE
WELDED JOINTS
WELDING