A CTE modified braze composition that can be utilized to manufacture a strong, gastight joint where at least one of the joining members comprises a ceramic (e.g., a ceramic or a cermet). The braze composition is formulated so as to reduce the thermal stress that results from the mismatch of thermal expansion coefficients between a ceramic joining member and the braze or other joining members. The braze composition comprises a braze alloy in powder, paste or bulk form mixed with one or more particulate or fibrous fillers that exhibit a low (i.e., no more than 6 ppm/K) or negative coefficient of thermal expansion. The braze composition can be used to join members, at least one of which comprises ceramic, and to a composite member produced by joining the two or more members.
STATEMENT OF GOVERNMENT SUPPORT
 This invention was made with government support under Contract DE-AC02-05CH11231 awarded by the United States Department of Energy to The Regents of the University of California for the management and operation of the Lawrence Berkeley National Laboratory. The government has certain rights in this invention.