Formation of CuAlO2 at the Cu/Al2O3 Interface and its Influence on Interface Strength and Thermal Conductivity

The criteria for the formation of a CuAlO2 reaction phase at the Cu/Al2O3 interface are explored. Oxygen solutes up to 2wt% were introduced into the copper first. The bonding was carried out at 1075 degrees C. The reaction phase was observed only when the oxygen solute in copper before bonding was higher than 1.3wt%. The CuAlO2 phase is polycrystalline and covers only part of the interface. The CuAlO2 grains interact with the crack, which improves the interface strength. As CuAlO2 is not continuous at the interface, the thermal conductivity of the Al2O3/Cu/Al2O3 laminate is affected little.