Methods and preliminary measurement results of liquid Li wettability

Area of Science:

• Materials Science
• Surface Science
• Physical Chemistry

Background:

• Understanding liquid metal-substrate interactions is crucial for various industrial applications.
• Lithium's unique properties necessitate precise characterization of its wetting behavior.
• Accurate measurement of contact angles is essential for predicting and controlling liquid metal behavior on surfaces.

Purpose of the Study:

• To investigate the wettability of liquid lithium on stainless steel substrates under high vacuum conditions.
• To evaluate the effectiveness of ellipse fitting for contact angle measurement compared to standard methods.
• To determine the influence of substrate temperature on lithium droplet contact angles and identify the critical wetting temperature.

Main Methods:

• High vacuum testing (< 3 × 10⁻⁴ Pa) of liquid lithium (Li) droplets on stainless steel.
• Acquisition of high-magnification images of Li droplets.
• Image processing using MATLAB® for edge point detection.
• Application of ellipse fitting to determine droplet shape and contact angles, contrasting with "θ/2" and polynomial fitting.

Main Results:

• Ellipse fitting provided reliable contact angle measurements across a wide range.
• The contact angle of liquid Li on stainless steel decreased progressively as substrate temperature increased.
• A critical wetting temperature for liquid Li on stainless steel was identified at approximately 290°C.

Conclusions:

• Ellipse fitting is a robust method for accurate contact angle determination of liquid metals.
• Substrate temperature significantly influences lithium wettability on stainless steel.
• The identified critical wetting temperature provides a key parameter for controlling lithium-stainless steel interactions.