Preferential Evaporation in Atom Probe Tomography: An Analytical Approach

Area of Science:

• Materials Science
• Analytical Chemistry
• Surface Science

Background:

• Atom probe tomography (APT) is a powerful technique for nanoscale chemical analysis.
• Accurate composition measurement in APT is crucial but can be affected by phenomena like preferential evaporation (PE).
• Preferential evaporation significantly biases apparent composition and is sensitive to analysis conditions.

Purpose of the Study:

• To develop and validate an analytical model for quantifying preferential evaporation in APT.
• To understand and predict the influence of APT analysis conditions on composition accuracy.
• To provide a method for optimizing APT parameters for reliable material analysis.

Main Methods:

• Development of a novel analytical model to describe preferential evaporation.
• Application of the model to analyze three distinct alloys: NiCu, FeCrNi, and FeCu.
• Validation of the model's predictions against experimental observations.

Main Results:

• The proposed model accurately quantifies preferential evaporation.
• It explains the dependence of PE on analysis temperature, pulse fraction, and pulse frequency.
• An energetic constant, linked to the atom evaporation energy barrier, can be derived from the model.

Conclusions:

• The developed analytical model offers a predictive tool to minimize preferential evaporation in APT.
• Optimizing APT analysis conditions based on this model enhances composition measurement accuracy.
• This work contributes to more reliable nanoscale chemical analysis of materials using APT.