Atom probe tomography analysis of WC powder

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Tantalum-doped tungsten carbide ((W,Ta)C) is a material with potential applications requiring precise composition control.
• Accurate quantification of tantalum (Ta) within the hexagonal mixed crystal carbide is challenging due to particle size.

Purpose of the Study:

• To develop and validate a method for preparing atom probe tomography (APT) specimens from fine (W,Ta)C powder particles (<1 μm).
• To quantitatively measure the tantalum content in hexagonal mixed crystal (W,Ta)C using APT.

Main Methods:

• Preparation of (W,Ta)C powder with maximized Ta content.
• Embedding the powder in copper for specimen preparation.
• Utilizing a focused ion beam--scanning electron microscope (FIB-SEM) workstation for in-situ lift-out of individual powder particles.
• Depositing the extracted particle onto a WC-Co cemented carbide specimen post.
• Employing laser-assisted atom probe tomography for quantitative analysis.

Main Results:

• A successful method for producing APT specimens from sub-micron (W,Ta)C particles was established.
• The developed technique enabled quantitative measurement of tantalum concentration within the (W,Ta)C.
• The feasibility of using laser-assisted APT for analyzing fine carbide powders was demonstrated.

Conclusions:

• The developed FIB-SEM lift-out and laser-assisted APT method is effective for quantitative analysis of tantalum in fine (W,Ta)C powders.
• This approach overcomes limitations in analyzing nanoscale materials with complex compositions.
• The study provides a reliable pathway for compositional analysis in advanced carbide materials.