Al–Si Thin Films Assisted Anodic Bonding of R2O–Al2O3–SiO2 Glass–Ceramics to Stainless Steel

In this work the anodic bonding of R2O–Al2O3–SiO2 glass–ceramic to stainless steel (No. 430), together with Al–Si thin films, was investigated for the first time. Relatively smooth and dense non-crystalline Al–Si thin films with a thickness of about 60 nm, were deposited on stainless steel surfaces by DC magnetron sputtering. The anodic bonding process was performed at 350°C and between 500 V and 800 V for 23 min in air and the micro-topography and compositions of the bonding interfaces were investigated by XRD, SEM and EDS. Bonding reaction products of lithium iron oxide (LiFe5O8 and Li5FeO4) were observed on the surface of glass–ceramics after anodic bonding had taken place. By comparing the bonding process of glass–ceramic to stainless steel, with and without an Al–Si thin film, our experimental results show that the presence of the Al–Si thin film resulted in a decrease in the bonding voltage and also assisted in the bonding process.