Wetting mechanism and bending property of Cu/Al2O3 laminated composites with pretreated CuO interlayer

Addition of oxygen in the interface between Cu and Al2O3 can significantly improve the wettability. In the present work, Cu/Al2O3 laminated composites were fabricated by bonding Cu foils with CuO-coated Al2O3 plates. Before bonding, the coated Al2O3 plates were pretreated at different temperature in the air. The effect of pretreated temperature on the interfacial microstructure, wettability and bending property were investigated. Phase composition in the interface after wetting test was characterized according to the thermodynamics of Cu–O system. The wetting mechanism and bending failure mode of Cu/Al2O3 laminated composites were also analyzed. Pretreated temperature significantly influences the wettability and bending strength of the composites. The contact angle decreased to about 22° when the pretreated temperature equal to 1100 °C. Continuous CuAlO2 in the interlayer is beneficial to the wettability between Cu melt and Al2O3, while other phases such as Cu2O and CuAl2O4 would increase the contact angle. Crack formation and propagation are the main failure mode of Cu/Al2O3 laminated composites during bending test. Different from the wettability, Cu/Al2O3 laminated composites fabricated with pretreated temperature at 1050 °C show the highest bending strength, although the contact angle is not the lowest on this condition. The reason is illustrated through analyzing the bending failure mode.