The distribution of O and N in the surface region of laser-patterned titanium revealed by atom probe tomography

D Kuczyńska-Zemła,G Sundell,M Zemła,M Andersson,H Garbacz

doi:10.1016/j.apsusc.2021.150193

Abstract

Direct Laser Interference Lithography (DLIL) has shown to be a promising technique to chemically and physically alter the surface of titanium. In this work, atom probe tomography analysis was performed on DLIL-treated titanium to obtain the chemical composition of the surface in maxima and minima interference positions. The analysis revealed that a multilayer structure consisting of oxide/oxynitride is formed at both positions; however, the chemical composition is altered differently between the two. The observed difference is believed to be due to an uneven heating and temperature distribution, which is demonstrated by thermal simulations.

Highlights

Amongst a variety of laser techniques, Direct Laser Interference Lithography (DLIL) has attracted great deal of attention
The temperature gradient causes a tension gradient to appear on the surface, which leads the flow of molten material at the maxima toward the colder areas at the minima positions
The atom probe tomography (APT) analysis shows that there is a significant difference in the stoichiometric chem ical composition between the two regions, which probably is a result of the uneven temperature distribution at the irradiated surface

Summary

Introduction

Amongst a variety of laser techniques, Direct Laser Interference Lithography (DLIL) has attracted great deal of attention. This is due to its flexibility to modify various types of materials [1,2,3,4,5] and for creating diversified surface topographies [6]. Titanium is melted only at the maximum intensity positions (constructive interfer ence) for a very short time and the molten material is transferred through Marangoni convection out to the interference minima positions (destructive interference) creating characteristic periodic patterns [11,12]. If the amount of molten material at the maxima position is enough to cover the whole distance to the minima position it results in a characteristic roundshaped periodic pattern

Methods

Results

Conclusion