INTERACTION OF SINGLE-CRYSTALLINE METAL FLUORIDES WITH TITANIUM-CONTAINING MELTS

Abstract

The wetting of solid titanium substrates with liquid lithium and magnesium fluorides was studied by the sessile drop method in 1 • 10^–3 Pa vacuum at 1173 and 1553 K, respectively. Titanium and fluorine were found to actively interact in the systems to change the titanium substrate surface profile, leading to a ‘hole’ in the contact area. The ‘solid titanium–liquid magnesium fluoride’ contact boundary geometry was examined and confirmed the potential to form gaseous products of the titanium–fluorine interaction. Such gaseous compounds prevent the wetting of alkaline-earth metal fluorides with titanium-containing melts at temperatures above 1400 K. These allows the materials made of alkaline-earth metal fluorides to be used as refractories for high-temperature melting, long-term homogenization, and casting of alloys with a high content of Ti, Zr, Hf, Nb, and V.