Process for sealing high-temperature fuel cells

Abstract

A process for sealing leaks gas spaces and/or gas channels between individual components of high-temperature fuel cells, includes introducing at least first and second and optionally further different gases at high temperature from the outside into the gas spaces and/or gas channels to be sealed off from one another, for flushing every leak with the first gas on one side and with the second or further gas on the other side. The first gas contains at least one gaseous compound that can be oxidized to form a metal ion-conducting and/or an oxygen ion-conducting oxide, and the second and optionally further gas contains oxygen and/or is able to give off oxygen. The first gas contains at least one oxidizable compound of at least one of the metals of an electrolyte material, a bipolar plate and electrodes of the fuel cells, and/or one element of the group including zirconium, nickel, calcium, magnesium, cerium and rare earth metal. A high-temperature fuel cell produced by the process includes individual components having previously leaking points therebetween. Inlays of metal ion-conducting and/or oxygen ion-conducting oxides are disposed in the vicinity of the previously leaking points. The inlays are formed of oxides of at least one of the metals of electrolyte material, a bipolar plate, electrodes, zirconium, nickel, calcium, magnesium, cerium, hafnium and rare earth metal.