Silver based reactive air brazes are alternative sealing materials for glass-ceramic materials for high temperature applications which can be processed in oxidizing atmospheres. These brazes are a new development of the established active brazes (AgTi-, AgCuTi-Base) for ceramic-ceramic- and ceramic-metal-joints, which must be handled in vacuum or in protective atmospheres. In comparison to glass based seals metallic brazes show a much higher ductility and offer a higher stability of joint components again thermal cycles and mismatches of the thermal expansion coefficients.