Electrochemical investigations during the abrasion of aluminum/titanium thin-film stacks in iodate-based slurry

The objective of this paper was to characterize the fundamental electrochemical behavior of thin aluminum-0.5% copper/titanium stack films before, during, and after abrasion in a commercially available alumina-based slurry containing iodate as an oxidant. A research apparatus in which electrochemical tests can be carried out during polishing was fabricated and used for this research. During the abrasion of the Al/Ti film stack, a sharp rise in corrosion potential (E_∞), on the order of 1000 mV, was measured. The transition was much sharper with the low-temperature (25°C) Al film than the high-temperature (475°C) Al thin film. The slower transition in open-circuit potential in high-temperature films is most likely due to a Ti-Al intermetallic compound formed at the Al/Ti interface. Additionally, the galvanic corrosion between Al and Ti during abrasion was investigated.