NASA 1996 SBIR Phase I


PROPOSAL NUMBER : 96-1 04.08-4000

PROJECT TITLE : Braze Joining of Dissimilar Materials for Furnace Components

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Joints between very dissimilar materials - e.g. metal-to-ceramic, are required in a number of aerospace, commercial and industrial systems. Brazing is often the preferred joining technique owing to compatibility, performance, cost and scalability advantages. However, the traditional brazed dissimilar material joints are likely to have a relatively low strength because of the high residual stress in the joint region. Also, brazing compounds frequently use active metal additions to promote wetting of the adherend surfaces. Though active metal additions do increase the joint strength in the short term, it has been shown that under elevated temperature operation, the joint strength falls with time. Foster-Miller's unique braze joint concept approach overcomes both brazing problems.

During Phase I, Foster-Miller will demonstrate an innovative, practical and low cost brazing technology for elevated temperature dissimilar material joints. The Phase I program will involve selection of materials to be joined with input from NASA COTR, design and build-up of the braze product form, fabrication of joint coupons, and testing consisting of physical characterization and mechanical, thermal cycling. The follow-on Phase II program will involve refinement of desgin, materials, procedures and process parameters. Phase II joint coupons will be subjected to a comprehensive test plan. A demonstration article of specific interest to NASA will be built during Phase II. The Phase II program will involve the following commercialization partners - braze product manufacturer, brazing service provider, NASA systems integrator.

POTENTIAL COMMERCIAL APPLICATIONS
Brazing is commonly used for joining of metallic and ceramic materials. The proposed technology has commercial applications involving attachment of dissimilar materials. These include: compact furnace components, hypersonic plane structures, rocket and gas turbine engines, X-ray and semiconductor sputtering targets, and industrial applications such as attachment of tubular products in pipelines, heat exchangers, chemical, oil drilling and mining slurry transport tubes, etc. Additionally, a reliable, practical and low cost joining technique for dissimilar materials will provide a new dimension for reducing component cost for designers, e.g. use different materials in strategic regions of a component.
NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR
Uday Kashalikar, Technology Area Leader
Foster-Miller, Inc.,
350 Second Avenue,
Waltham, MA 02154-1196
NAME AND ADDRESS OF OFFEROR
Foster-Miller, Inc.,
350 Second Avenue,
Waltham, MA 02154-1196