Femtosecond Laser-Induced Periodic Surface Structures on 2D Ti-Fe Multilayer Condensates.

Oleksandr V Kuznietsov,Anatoliy A Demchishin,Anatoliy V Demchishin,Stefano Bellucci,Ivan Saldan,Volodymyr Babizhetskyy,Iaroslav Gnilitskyi,George D Tsibidis

doi:10.3390/nano11020316

Abstract

2D Ti-Fe multilayer preparation has been attracting increased interest due to its ability to form intermetallic compounds between metallic titanium and metallic iron thin layers. In particular, the TiFe compound can absorb hydrogen gas at room temperature. We applied femtosecond laser pulses to heat Ti-Fe multilayer structures to promote the appearance of intermetallic compounds and generate surface nanostructuring. The surface pattern, known as Laser Induced Periodic Surface Structures (LIPSS), can accelerate the kinetics of chemical interaction between solid TiFe and gaseous hydrogen. The formation of LIPSS on Ti-Fe multilayered thin films were investigated using of scanning electron microscopy, photo-electron spectroscopy and X-ray diffraction. To explore the thermal response of the multiple layered structure and the mechanisms leading to surface patterning after irradiating the compound with single laser pulses, theoretical simulations were conducted to interpret the experimental observations.

Highlights

The TiFe intermetallic compound (IMC) is considered a promising hydrogen storage material, but this IMC requires initial activation to effectively absorb hydrogen gas [1,2,3,4,5,6].Using high-pressure torsion (HPT), TiFe can reversibly absorb ~1.4–1.7 wt.% H2 in practice at room temperature without thermal activation [1]
Laser treatment with Laser Induced Periodic Surface Structures (LIPSS) formation leads to the structuring of the surface by creating periodic longitudinal ripples on
Experimental results obtained by Scanning Electron Microscope (SEM) and XRD suggested that for the prepared the first layer (Ti)-Fe multilayers, alloying between metallic titanium and metallic iron resulted in the appearance of a TiFe compound

Summary

Introduction

Using high-pressure torsion (HPT), TiFe can reversibly absorb ~1.4–1.7 wt.% H2 in practice at room temperature without thermal activation [1]. Effective activation of air-exposed TiFe alloy might be performed mechanically using cold rolling [3,4] or ball milling [3,5,6]. These procedures help to restore the hydrogenation capability of TiFe. Because of the low price of production and activation of TiFe, it can be used in hydrogen storage tanks, fuel cells and secondary batteries. Thin films of pure TiFe can be used as hydrogen sensors at room temperature, but in order to charge/discharge them faster, a more developed surface structure is needed

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Conclusion