Development of microstructure of the anodically-bonded interface between aluminum and borosilicate glass

A voltage was applied to the interfaces between borosilicate glass and Al deposited layer, and changes in the microstructure around the interfaces were investigated by transmission electron microscopy. At the Al/glass interface, two types of the oxide, a layer at the bond interface and fibers growing from the layer into the glass, were observed. Both these oxide structures were *g-Al2O3, and they grew epitaxially from the Al layer. In the early stage of the voltage application, the oxide layer formed and grew, after that the oxide fibers began to form. After the appearance of the oxide fibers, growth of the oxide layer stopped. The mechanism of formation and growth of these oxide structures is proposed from the viewpoint of the transportation of Al ions in the glass and the *g-Al2O3.