The mechanism of the welding between silica glass and 304 stainless steel using nanosecond fibre laser

Devices consisting of glass and metal are widely applied to many fields. With the miniaturisation and the expansion of application fields of these devices, the requirement of micro-joining between glass and metal is becoming higher. In this work, silica glass and 304 stainless steel were welded by the infrared nanosecond fibre laser. The welding quality was optimised by varying the laser parameters. The joint strength reached 16.39 MPa. The mechanism of the welding between the two materials was investigated. The results demonstrated the elemental diffusion in the interface between silica glass and 304 stainless steel under laser heating, where Fe, Cr and Si were the crucial factors in forming the welds. During the elemental diffusion, Cr was much easier to diffuse into glass than Fe. In the interface, Fe-O-Si bonds were observed. Moreover, increasing Cr content in the interface is a probable approach to improve the joint strength.