Corrosion Resistant Aluminum
Treatment of Vapor Deposited Aluminum for Corrosion Resistance and Better Barrier Performance.
Vacuum deposited aluminum is super-reactive until it has been passivated. Passivation mainly occurs after the aluminum has been exposed to moisture in ambient air - especially during the the slitting/rewinding process. The hydrated aluminum oxide that forms is a poor barrier to moisture vapor and oxygen. This makes the bulk of the aluminum highly susceptible to corrosion. Additionally, prior to exposure to ambient air - while still in the vacuum chamber - freshly deposited aluminum reacts with the back side of the substrate during the rewind process. This often results in "blocking" during slitting, which negatively impacts barrier performance.
Plasma treatment of vapor deposited aluminum, immediately after deposition, results in the formation of a high quality aluminum oxide layer that works to improve barrier performance and corrosion resistance. improves corrosion resistance and reduces bonding of the aluminum with the backside of the polymer film. Reduction of bonding between the aluminum and the polymer film, reduces pick-off of the aluminum during slitting. Pick-off reduction leads to significant improvement in the barrier properties of the metallized films.