Tritium as an Unambiguous Isotopic Tracer for Nanoscale Hydrogen Analysis by Atom Probe Tomography

TL;DR

This paper demonstrates the use of tritium as an unambiguous isotopic tracer for nanoscale hydrogen detection in metals via atom probe tomography, providing a new approach to study hydrogen-related phenomena.

Contribution

It introduces tritium as a novel isotopic marker for nanoscale hydrogen analysis with atom probe tomography, overcoming background hydrogen issues in materials research.

Findings

Tritium can be effectively detected and tracked in metals using APT.

Surface oxide layers influence tritium release during thermal desorption.

The combined use of tritium and APT offers fundamental insights into hydrogen localization.

Abstract

Accurate nanoscale detection of hydrogen is essential for understanding hydrogen-related phenomena in materials, yet conventional deuterium tracing is often complicated by residual background hydrogen. This study evaluates tritium as an unambiguous isotopic marker for nanoscale hydrogen analysis in metals using atom probe tomography (APT). Titanium was selected for its ability to incorporate hydrogen isotopes, providing a suitable platform for tritium detection. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electron backscatter diffraction (EBSD) were performed prior to tritium charging to characterize the initial composition and microstructure. APT analysis in laser-mode before and after tritium charging, at three post-charging intervals, enables tracking of tritium incorporation over time. Thermal desorption analysis (TDA) confirmed the presence of tritium and complemented the SIMS measurements, highlighting the role of the surface oxide layer in modulating tritium release. This work serves as a fundamental benchmarking study for leveraging tritium and APT as a combined tool for understanding the nanoscale location of hydrogen in materials, being relevant for interpreting local processes related to e.g., hydrogen embrittlement.