Interfacial microstructures and glass strengthening in anodic-bonded Al sheet/glass and sputtered Al film/glass

摘要

Two anodic bond interfaces were fabricated at 300 ℃, between glass and either an Al sheet or a sputter-deposited Al film, and their microstructures and bending strengths were comparatively studied. In the Al sheet/glass interface, numerous local intrusions of crystalline Al_2O_3 with a long (100-350 nm) dendritic structure were formed in the glass adjacent to the aluminum. However, in the sputter-deposited At film/ glass interface, a continuous, thin (～30 nm) amorphous layer with Al-oxide nanocrystals along the interface was present without the formation of dendhtes after anodic bonding. The dendritic structures in the Al sheet/glass are attributed to an electrostatic instability imposed by the roughness and local oxidation of the Al sheet surface or, presumably, by microheating via gas discharge at the interface. The bending fracture strength for both types of bonded glasses increased by approximately 1.7 times compared with that of the bare glass due to the interfacial reaction.