NASA 1998 SBIR Phase I


PROPOSAL NUMBER: 98-1 19.09-8008a

PROJECT TITLE: Multilayer Braze Foils for Joining Silicon Carbide to Inconel 600

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Silicon carbide has many materials properties that make it desirable for use at extreme temperatures and atmospheres. However the manufacture of complex silicon carbide components as a single piece is both difficult and expensive. Joining technologies are required that will withstand the extreme conditions to which the silicon carbide components will be exposed. This SBIR Phase I proposal concerns the development of an improved active metal brazing system for joining silicon carbide to Inconel 600. This system avoids the formation of brittle intermediate phases and will operate at temperatures above 1000 C without degradation. The multilayer braze foil technology incorporates layers which prevent formation of brittle chromium carbides and excessive diffusion of silicon from the substrates. This is accomplished by forming a post reaction equilibrium in silicon concentration, and uses reactive metal layers to trap carbides before large chromium carbide grains can form. The resulting joint is expected to have long term strength in excess of 400 MPa. Testing of the joint will consist of four point bend testing in addition to x-ray diffraction and surface analysis. NASA application for bonded silicon carbide components include parts for the Solar Probe and furnaces for the Space Shuttle and the Space Station.

POTENTIAL COMMERCIAL APPLICATIONS

Commercial applications of a strong brazed joint for silicon carbide/Inconel include high temperature parts such as nozzles and combustion chambers for gas turbines, turbine rotors for combustion engines, and the bodies of heat exchangers. Silicon carbide parts for fusion reactors are another potential application.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR

Thomas F. Barton
Eltron Research Inc
5660 Airport Blvd #105
Boulder , CO 80301-2340

NAME AND ADDRESS OF OFFEROR

Eltron Research Inc
5660 Airport Blvd #105
Boulder , CO 80301-2340