Two reports present additional details about the method described in "Reaction-Forming Method for Joining SiC-Based Ceramic Parts" (LEW-16661), NASA Tech Briefs, Vol. 23, No. 3 (March 1999), page 50. To recapitulate: A carbonaceous mixture (typically a paste) is applied to a joint between parts. The parts are clamped together and heated to a temperature of 115±5 °C for 10 to 20 minutes; this action partly cures the mixture, gluing the parts together with just enough strength that one need not clamp the parts during subsequent processing. Silicon or a silicon alloy in tape, paste, or slurry form is applied to the joint region. The parts are heated to a temperature between 1,250 and 1,425 °C for 5 to 10 minutes, causing the silicon or silicon alloy to melt, infiltrate the joint, and react with carbon. The finished joint, which is typically as strong as the parent material, contains silicon carbide with silicon and other phases. The amounts of the phases can be adjusted, by choice of the compositions of the reactants, to obtain joints with tailorable microstructures and thus tailorable thermomechanical properties.

This work was done by Mrityunjay Singh of NYMA, Inc., for Glenn Research Center. To obtain copies of the reports, "A New Approach to Joining of Silicon Carbide-Based Materials for High Temperature Applications" and "Affordable, Robust Ceramic Joining Technology (ARCJoinT)," access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp  under the Materials category.

Inquiries concerning rights for the commercial use of this invention should be addressed to

NASA Glenn Research Center,
Commercial Technology Office,
Attn: Steve Fedor,
Mail Stop 4 —8,
21000 Brookpark Road,
Cleveland, Ohio 44135.

Refer to LEW-16827.


NASA Tech Briefs Magazine

This article first appeared in the April, 2000 issue of NASA Tech Briefs Magazine.

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