Wetting behavior at the free surface of a liquid gallium-bismuth alloy: An X-ray reflectivity study close to the bulk monotectic point

TL;DR

This study uses X-ray reflectivity to investigate how a liquid gallium-bismuth alloy's surface becomes wet as it approaches the bulk monotectic temperature, revealing complete wetting behavior at a tetra point.

Contribution

It provides the first detailed X-ray reflectivity analysis of wetting behavior near the monotectic point in a Ga-Bi alloy, highlighting the transition to complete wetting.

Findings

Formation of a thick wetting film near the monotectic temperature

Observation of complete wetting at a tetra point

Correlation between bulk transition and surface wetting behavior

Abstract

We present x-ray reflectivity measurements from the free surface of a liquid gallium-bismuth alloy (Ga-Bi) in the temperature range close to the bulk monotectic temperature $T_{mono} = 222$C. Our measurements indicate a continuous formation of a thick wetting film at the free surface of the binary system driven by the first order transition in the bulk at the monotectic point. We show that the behavior observed is that of a complete wetting at a tetra point of solid-liquid-liquid-vapor coexistance.