Enhancing the welding joint strength of aluminum nitride ceramic and polycarbonate by micro-texture treatment

Ceramic microfluidic chips with high similarity to real bone have great potential in bone-related fields. Packaging the transparent polymer window on the top of the ceramic microfluidic chip makes it possible to monitor the internal conditions of the chip in real time. Thus, a dual wavelength laser welding method of joining aluminum nitride (AlN) ceramics and polycarbonate (PC) is proposed to achieve the high-strength joining of ceramics to polymers. The micro-textures are generated after micro-texture treatment on the AlN ceramic surface. Subsequently, AlN ceramic and PC are welded using dual wavelength laser welding. The influences of the micro-texture parameters and welding parameters on welding joint strength are investigated. The results show that micro-texture parameters change the contact area at the welding joint, thus affecting the welding joint strength. The optimal micro-texture parameters are 200 μm of micro-texture size, 150 μm of micro-texture spacing and 200 μm of micro-texture depth. Under the optimal micro-texture parameter, the welding joint strength attends to 17.9 MPa. The appropriate welding parameters provide the PC with enough heat input to melt and bond with the micro-texture interface adequately. The optimal 980 nm laser power is 110 W, 1710 nm laser power is 15 W and welding speed is 2 mm/s.