Surface profiling of lithium with a laser-desorption mass-spectrometer microprobe

Area of Science:

• Materials Science
• Analytical Chemistry
• Surface Science

Background:

• Chromium-plated rolled-joint hubs are critical components in various mechanical systems.
• Understanding lithium distribution on their crevice surfaces is essential for performance and failure analysis.
• Conventional methods for surface profiling can be time-consuming or lack sufficient resolution.

Purpose of the Study:

• To develop and evaluate a novel laser-desorption mass spectrometry (LDMS) microprobe for profiling lithium (Li) distributions.
• To compare the performance of LDMS with secondary ion mass spectrometry (SIMS) for Li surface profiling.
• To assess the correlation between Li distribution images and surface topographical features.

Main Methods:

• Development of a laser-desorption mass-spectrometer microprobe system.
• Utilizing a single laser pulse for desorption and ionization of surface species.
• Detection of Li+ ions using a time-of-flight mass spectrometer.
• Acquisition of surface Li distribution images with sub-10 micrometer resolution.
• Comparative analysis with SIMS, secondary electron microscopy (SEM), and atomic force microscopy (AFM).

Main Results:

• The LDMS microprobe successfully profiled Li distributions on crevice surfaces of Cr-plated rolled-joint hubs.
• High-resolution images (<10 micrometers) of Li surface distribution were obtained.
• LDMS-generated images provided qualitative information comparable to those from SIMS.
• Surface topographical features were analyzed using SEM and AFM to contextualize Li distribution.

Conclusions:

• The developed LDMS microprobe is an effective tool for analyzing Li surface distributions.
• LDMS offers a viable alternative to SIMS for qualitative assessment of Li distribution on complex surfaces.
• This technique aids in understanding material behavior and potential failure mechanisms in plated components.