15 research outputs found
Investigations on the formability of a tungsten alloy by use of acoustic emission analysis
Investigations on the formability of a tungsten alloy by use of acoustic emission analysis
FlieĂźkurven von hochschmelzenden Metallen als Grundlage zur Simulation von Umformprozessen
Minimization of Friction Influence on the Evaluation of Rheological Parameters From Compression Test: Application to a Forging Steel Behavior Identification
Probing Transformations of Relevance in Catalysis on a Single Oxide Layer: Fe on TiOx/Pt(111)
The evolution of a Fe/z'-TiOx/Pt(111) model catalyst in ultrahigh vacuum, studied by advanced surface science tools, reveals various phenomena occurring in different temperature ranges. In the room temperature (RT) < T < 460 K range, the deposited Fe atoms assemble as heterogeneous Fe and FeOx nanoparticles (NPs), templated by the ordered array of defects (troughs and picoholes) of the oxide film. At 460 < T < 810 K, FeOx NPs become predominant, and a metastable FeOx/TiOx mixed oxide is formed, assisted by the interdiffusion of Fe through the oxide into the Pt substrate, which triggers the z'-TiOx structure transformation into a different TiOx phase with a hexagonal pattern. At 810 < T < 1000 K, a Fe-mediated extraction of Pt produces Pt(111) islands, surrounded and partly encapsulated by the same z'-TiOx phase,
demonstrating the intrinsic high stability of the ultrathin oxide film.
This represents one of the first examples of a phase transformation in a ultrathin oxide layer induced by an external metal deposit