Direct welding of dissimilar ceramics YSZ/Sapphire via nanosecond laser pulses

The joining of YSZ and sapphire was achieved through the utilization of nanosecond laser pulses. The microstructure, mechanical properties and forming process of the YSZ/Sapphire joint were systematically studied. The joint consists of an amorphous region guided by the temperature gradient and a dendritic recrystallization region. The amorphous region is situated centrally within the joint, while the recrystallization region surrounds it in a distributed manner. The reason for this phenomenon lies in the fact that the welding process occurring in the central region of the joint, and the extreme cooling prevents Al³⁺, Zr⁴⁺ and O^2- ions from forming regular crystal phases. During this study when the laser power is set at 9 W and the scanning speed is adjusted to 80 mm/s, optimal welding interface performance can be achieved, resulting in a maximum joint shear strength of 32 MPa. This study provides a new idea for rapid and efficient welding of advanced ceramic.