Eutectic Gallium‐Indium as a Potential Non‐Toxic Replacement in Mercury Intrusion Porosimetry

ABSTRACT

The eutectic gallium‐indium alloy (eGaIn) is introduced as a potential non‐toxic, sustainable replacement in Mercury Intrusion Porosimetry (MIP). Contrary to the widespread misconception that gallium alloys are unsuitable for this technique due to their wetting behavior, this study shows that porosimetry measurements with non‐oxidized eGaIn are comparable to those obtained with mercury. A newly developed “eGaIn Filling Station” enables oxygen‐free preparation of standard penetrometers, facilitating high‐pressure analysis using commercially available porosimeters. Five certified and two non‐certified reference materials were analyzed with mercury and eGaIn, revealing nearly identical pore‐size distributions and total intruded volumes. Within the investigated pore‐size range, the findings show that non‐oxidized eGaIn faithfully reproduces key mercury‐based intrusion metrics while eliminating its toxicity and environmental hazards. This work provides the first demonstration of a practical alternative to mercury for MIP, offering a safe and sustainable route to preserve this essential characterization technique in compliance with global mercury regulations.