SURFACE-TENSION MEASUREMENTS OF REFRACTORY LIQUID-METALS BY THE PENDANT DROP METHOD UNDER ULTRAHIGH-VACUUM CONDITIONS - EXTENSION AND COMMENTS ON TATE LAW

The pendant drop method, used in an ultrahigh vacuum drop tube, allowe d new determinations of the liquid surface tension of the refractory m etals. After a description of the melting apparatus, the amazing repro ducibility in terms of droplets masses (congruent-to 0.6%) observed is discussed herein. Evidence is given of the harmful action of hydrogen bubbles contained in the commercial rods. Working with very thin wire s (down to 0.3 mm), a variation curve for the Harkin's correction fact or of Tate's law in its untabulated range is proposed. The validity of the representation of this factor is discussed via a dimensional anal ysis. Finally, new values of sigma(LV) for pure Re (2.510 J m-2), W (2 .310 j M-2 ), Ta (2.010 j M-2) , Nb (1.840 J m2), Ir (2.140 J m-2), an d Zr (1.435 J m-2) are proposed.