a method for joining two ceramic parts , or a ceramic part and a metal part , and the joint formed thereby . the method provides two or more parts , a braze consisting of a mixture of copper oxide and silver , a diffusion barrier , and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together . the diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze , a heterogeneous component of the braze , a separate layer bordering the braze , or combinations thereof . the oxidizable metal is selected from the group al , mg , cr , si , ni , co , mn , ti , zr , hf , pt , pd , au , lanthanides , and combinations thereof .