Surface Modification of Steel Foils by Depositing Cr/Al or Al/Cr Thin Films: Effect of Rapid Heat Treatment

In this study, Al and Cr films were deposited onto steel substrates, and the film growth and microstructure were tracked. In the first set of experiments, Al was directly deposited onto steel, and Cr films were then deposited on top of the formed Al films. In the second set of experiments, it was vice versa ; that is, Cr films were deposited onto the steel substrate, followed by Al film deposition. This technique was aimed at controlling the reflection property of the steel substrate to enable using steel foils for flexible display fabrication. It was observed that temperature significantly influenced grain formation and growth processes. When the temperature reached 550 ∘ C, segregation occurred in the system where Cr contacted the steel, and Al was on the top layer. However, a similar phenomenon was not observed in the steel/Al/Cr system. The reflection value significantly decreased from 92 to 5–7 %, owing to these segregations.