Structural Transformations on a Platinum Surface under Mechanical Tension

Abstract

The effect of uniaxial tension on the structure of a recrystallized platinum surface is investigated using low-energy electron diffraction (LEED). The initial LEED patterns indicate that the (111) facet emerges on the surface of a platinum foil after a series of heating cycles under vacuum and in oxygen. After loading at ∼80 MPa, the clean platinum surface is characterized by systems of regular and irregular atomic terraces. The regular terraces have a (9(111) × 100) structure. As the load increases to 90–100 MPa, the ordered arrangement of terraces transforms into a disordered arrangement. After the samples are held under these loads for ∼2 h, the surface structure undergoes a transformation into the diffraction-disordered state. Under tensile deformation, the island structure of graphite molecules on the recrystallized platinum surface containing ∼10 at. % C also undergoes a transformation.