Investigation of gallium and indium during melting

Abstract

It has been shown for gallium of 99.9999 wt.% purity that when small weighed amounts of the metal placed in special crucibles are superheated to 400°C in a vacuum of 10 −7 Pa, the acute-angled shapes of the starting sample are retained, and platelike protrusions appear on the surface in the case of partial coagulation. Structural changes in indium 99.98 wt.% purity were studied using transmission electron microscopy and microdiffraction during heating to a temperature of 190°C above the melting point. We managed to superheat 50–100 nm thick film samples, having an ultrafine-dispersion fragmentation into plates in the initial state, to a temperature well above the melting point, with the external shapes being retained. In the case of partial coagulation of the sample, the formation of thin films 3–10 nm thick was observed; the films were similar to solid films in appearance but had an electron diffraction pattern typical of a liquid, with texture elements. The size of the coherent scattering regions was about 2.5 × 15 nm. The chemical composition of the film corresponded with indium.