THE SURFACE TENSION OF LIQUID TRANSITION METALS AT THEIR MELTING POINTS

Abstract

S>Liquid surface tensions of copper and 18 Group IV-A to VIII transition metals (Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Ru, Rh, Pd, Os, Ir, Pt, Fe, Ni, Co) were measured by the static pendant-drop and dynamic drop-weight methods on the same rod sample. The drops were formed by electronbombardment heating in high vacuum. Application of necessary corrections enabled determination of surface tensions to plus or minus 2% and agreement between methods to plus or minus 1 to 4% for all the metals studied. Evidence is presented that the liquid surface was well screened by metal vapor, suggesting negligible adsorption of gaseous impurities and that the surface tensions measured are characteristic of the metals involved. Correlations between liquid surface tension and melting point, molar volurae, heat of vaporization, and atomic number are presented and discussed. Teraperature coefficients of surface tension were calculated using Eotvos' law. (auth)