Density and ultrasound velocity in Ga-Bi melts

Abstract

Density d temperature dependences of Ga-Bi melts with 0, 10.2, 16.2, 29.8, 42.0, 51.6, 61.5, 80.0 and 100 at.%Bi were measured using absolute gamma-absorption technique with accuracy of 0.2 to 1.5% (depending on bismuth concentration). In addition, temperature dependences of ultrasound velocity v(s) were determined for the samples with 11.0, 16.7, 29.8 and 100 at.% Bi. The accuracy in the acoustic measurements was higher than 0.3%. The special scanning equipment for the gamma-densitometer has allowed to measure density of co-existing phases below the separation cupola. The obtained values coincide with reference data within the declared accuracy. An anomalous behavior of ultrasound velocity (deviation of the v(s)(T) from linear dependences) and significant increase of ultrasound attenuation were discovered for the samples with 16.7 and 29.8 at.% Bi at the temperatures of 70 to 100 K above the separation cupola. Using the experimental data, the thermal expansion coefficient, molar volume and adiabatic compressibility were calculated. All theses characteristics demonstrate linear behavior similar to ideal solutions.