Research on the interfacial microstructure and mechanical properties of glass/Mg joint prepared by anodic bonding and vacuum diffusion bonding

Abstract

The joining of glass and Mg by a combination of anodic bonding and vacuum diffusion bonding with Al as the interlayer was achieved in one step. The microstructures of glass/Mg dissimilar joints were analyzed using optical microscopy, SEM, and EDS. The results show that the bonding interface was joined well without any voids and cracks. Na+ and Ca2+ depletion regions would be produced in the glass near the Al foil, where the width of the Na+ depletion region was larger than that of the Ca2+ depletion region. In addition, the content of Al element in the depletion regions increased, and the diffusion of Al into the depletion regions was responsible for the successful glass/Al bonding process. Al3Mg2 and Al12Mg17 intermetallic compound (IMC) layers were formed between the Al and Mg. The anodic bonding process and the vacuum diffusion bonding process were independent of each other: and the thickness of the IMC layer increased with the increase of the diffusion bonding time, while the width of the Na+, Ca2+ depletion region remained constant; Meanwhile, the variation of the anodic bonding parameters only affected the width of the depletion layer and had no effect on the thickness of the Al3Mg2 and the Al12Mg17 IMC layer. The fracture position of the sample changed from the Al/Mg bonding interface to the glass/Al bonding interface as the thickness of the IMC layer increased. The maximum tensile strength of 14.6 MPa was obtained by vacuum diffusion bonding at 450 °C for 20 min and anodic bonding under 400 °C and 800 V.