Crack formation mechanisms in Al2O3/Kovar brazed joint

AbstractJoining of metal to ceramic is difficult owing to the formation of cracks at the interface of brazed joint. In the present paper, the crack forming metallurgical mechanisms is studied primarily. The vacuum brazing experiments of ceramic Al2O3 and Kovar, Ni, Fe or Co metals are all conducted. It can be obtained that the cracks could be formed at the Al2O3–Kovar and Al2O3–Fe joint, but not at the Al2O3–Ni and Al2O3–Co joint. In addition, the interfacial morphology and compound composition near cracks are confirmed. It can be concluded that the formation of intermetallic compound FexTiy is the main reason why cracks formed.