Effect of Exogenous Zirconia Nanophases on the Structural Properties of the Sulfur- and Tin-Containing Nickel Melts

The surface tension and the density of the nickel melts with introduced ZrO₂ nanoparticles are studied by the sessile drop method using a digital camera and computer processing of images. The revealed differently directed effects of nanoparticles on the surface tension in the Ni–Sn and Ni–S systems points to a change in the structure of the melt–gas surface layer. The nanoparticles are shown to affect the adsorption of surfactants, and the surface layer is likely to consist of adsorbed Ni + (ZrO₂–surfactant) ensembles. The ZrO₂ content in a metal is determined using the technique of separate determination of the zirconium content dissolved in a metal and zirconium in the form of ZrO₂. It was found that, at 0.10 wt % ZrO₂ initially present in a metal, 0.021–0.031 wt % ZrO₂ are retained in samples; that is, about 70 rel % ZrO₂ are removed to the interface in the form of ensembles. Auger spectroscopy analysis of the Ni–Sn–ZrO₂ surface film detected 5–10 rel % Zr in the surface layer.