Formation processes of the surface oxidized layer on Al-Ti alloy films

Abstract

Characterization and formation process of the surface oxidized layer formed on the surface of Al‐Ti alloy thin films are examined with respect to the alloy composition and alloy film structure. While Al atoms within the alloy films form a thin surface Al2O3 layer by preferential oxidation in the initial stage of oxidation regardless of the alloy composition or its structure, for the case of a sufficiently Al‐rich alloy composition, a surface Al2O3 layer comparable to that formed on the Al surface is formed, in which Ti atoms in the alloy can exist beneath the Al‐oxide layer in the metal state, and the surface oxide layer protects the alloy film from further oxidation even after the oxidation treatment at 300 °C for 1 h. On the other hand, for a Ti‐rich alloy composition that cannot guarantee the preferential oxidation of the Al surface, the oxidation of Ti occurs due to the oxygen atoms introduced through a thin Al2O3 as well as the associated oxidation of Al, the oxidation easily progresses inside the alloy. It has been found that even for Al‐Ti alloys with approximately the same composition, the oxide layer thickness is different between the metal compound film and the amorphous alloy film. It is found that the oxide layer formed on the compound film is thinner. This is attributed to the difference in the interaction as a chemical bonding inherent in the alloy structure between the compound phase and the amorphous phase during the ionization process of metal as a reaction species. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(8): 58–66, 2000

Growth of Self‐Passivating Oxide Layers on Aluminum—Pressure and Temperature Dependence

“…In this respect, the oxidation of Al-containing metal alloys has been investigated in detail, with special focus on W-Al, Ti-Al and Ni-Al systems. [3][4][5] The self-passivating oxide grown on NiAl(110) takes hereby a special role as its structure, composition, and electronic properties were studied down to atomic length scales with various surface-science techniques. [6,7] Aluminum oxidation has also been identified as a prototype reaction that proceeds according to the Cabrera-Mott scheme.…”