Mismatch design of AuxNi1-x(111)/α-Al2O3(0001) interfaces and their correlative investigation by X-ray diffraction and electron microscopy

Dierner M, Will J, Landes M, Yokosawa T, Przybilla T, Hübner S, Zech T, Götz K, Lahn L, Kasian O, Unruh T, Spiecker E (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Acta Materialia Elsevier

Book Volume: 297

Article Number: 121287

DOI: 10.1016/j.actamat.2025.121287

Abstract

In this contribution, the influence of lattice mismatch on the structure and chemistry of the AuxNi1-x/α-Al2O3 interface is investigated. For this, Au/Ni bilayers are deposited on α-Al2O3(0001) surfaces, annealed at elevated temperatures and quenched to room temperature to produce micron-sized AuxNi1-x alloy particles by solid-state dewetting. The lattice mismatch is controlled by the Au concentration x, which is adjusted by the relative thickness of the Au and Ni layers. Electron backscatter diffraction revealed the formation of particles with a mismatch-dependent epitaxial orientation relation (OR). Particles with a positive lattice mismatch show a clear dominance of OR1 with AuxNi1-x(111)[11¯0]||α-Al2O3(0001)[101¯0], while for particles with a negative mismatch a strong increase of OR2 with AuxNi1-x(111)[112]||α-Al2O3(0001)[101¯0] is recorded. The occurrence of a near coincident site lattice is identified as a possible stabilizer for OR2. Correlative in-plane (IP) XRD and TEM in plan-view and cross-section geometry revealed (i) a semi-coherent interface for a positive mismatch of 0.68 %, indicated by a prominent diffuse background in IP XRD and moiré fringes in TEM plan-view images, (ii) a nearly coherent interface for reduced mismatch of 0.21 %, marked by a decrease in diffuse background and an interface structure similar to that of lattice-matched Pd/α-Al2O3(0001) and (iii) an incoherent interface with OR2 for negative mismatch. Comparison of experimental and simulated micrographs confirmed an Al2 termination of the Al2O3(0001) substrate for all samples. Additionally, chemical analysis revealed Au segregation at the interface, which is discussed in terms of mechanical stress effects and electrochemical interactions across the AuNi-Sapphire interface.

Authors with CRIS profile

Martin Dierner Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Johannes Will Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Michael Landes Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Tadahiro Yokosawa Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Thomas Przybilla Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Susanne Hübner Lehrstuhl für Werkstoffwissenschaften (Biomaterialien) Tobias Zech Lehrstuhl für Kristallographie und Strukturphysik (ICSP) Klaus Götz Lehrstuhl für Kristallographie und Strukturphysik (ICSP) Leopold Lahn Professur für Materialien für die elektrochemische Energiekonversion Olga Kasian Professur für Materialien für die elektrochemische Energiekonversion Tobias Unruh Professur für Nanomaterialcharakterisierung (Streumethoden) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)

How to cite

APA:

Dierner, M., Will, J., Landes, M., Yokosawa, T., Przybilla, T., Hübner, S.,... Spiecker, E. (2025). Mismatch design of AuxNi1-x(111)/α-Al2O3(0001) interfaces and their correlative investigation by X-ray diffraction and electron microscopy. Acta Materialia, 297. https://doi.org/10.1016/j.actamat.2025.121287

MLA:

Dierner, Martin, et al. "Mismatch design of AuxNi1-x(111)/α-Al2O3(0001) interfaces and their correlative investigation by X-ray diffraction and electron microscopy." Acta Materialia 297 (2025).

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