Brazing of carbon–carbon composites to Nimonic alloys

• DOI: 10.1007/s10853-009-3893-x
• Publication Date: 2009-09-29T18:50:54Z
• Authors: N. V. Moutis; C. Jimenez; X. Azpiroz; Th. Speliotis; C. Wilhelmi; S. Messoloras; K. Mergia
• Keywords: Nimonic; Brazing; Carbon fibers; Overlayer; Chromium carbide

Industrially produced Cf/C ceramic composites have been brazed to Nimonic alloys using a TiCuSil filler metal. Ιn order to accommodate the different linear coefficients of expansion between ceramic and metal as well as to provide compatibility between the surfaces to be joined, the Cf/C surface was metallized through the deposition of a chromium layer. Subsequent heat treatments were carried out to develop intermediate layers of chromium carbides. Crack-free joints have been produced and shear tests show that failure occurs within the composite. At the Cf/C-filler interface a layered structure of the metallic elements is observed. Titanium is depleted from the filler zone and interacts with the carbon to form carbides. In the filler region, Ag and Cu rich regions are formed.