The effects of Tl additions on a wetting-related adsorption transition in liquid Ga–Pb alloys

This paper reports the effects of Tl additions on Pb adsorption to the surface of liquid Ga–Pb alloys. Adsorption of Pb and Tl was measured by Auger electron spectroscopy, as a function of temperature, for six ternary alloys ranging in composition from Ga–3.33×10−1 at.% Pb–1.65×10−1 at.% Tl to Ga–1×10−4 at.% Pb–5×10−5 at.% Tl, all having a 2:1 ratio of Pb:Tl. The temperature of the prewetting critical point in binary Ga–Pb alloys had previously been estimated to lie at about 240 K. The motivation for this work was to raise the temperature of the prewetting critical point by the addition of Tl. However, the results show that whereas Pb adsorption is enhanced by Tl additions, as expected from simple models, the estimated temperature of the prewetting critical point is lowered even further to about 215 K.