Wetting of nonmetallic materials by metal melts in the conditions simulating conditions of space vacuum and an atmosphere of the Moon

Abstract

Wetting of ionic compounds (oxides and fluorides) and graphite by Al, In—Ti and Cu—Ti in an interval of temperatures 700––1200 °С in vacuum 1×10^-2–– 5×10^-4 Pa by a sessile drop method with use of additional investigation methods was studied. The contact angles at wetting of substrates by aluminum at a different degree of vacuum are approximately equal. Contact angles decrease at introduction in In already 5% (at.) Ti for MgF₂, SrF₂, CaF₂, SiO₂, Al₂O₃ and graphite accordingly up to 8, 10, 10, 20, 25, 42 degree. On the basis of results on wetting, it is possible to assert that the vacuum is lower 10^-3 Pa is sufficient for researches of capillary characteristics of metal melts. The additional methods of researches (capillary purification of alloy), and also drawing of metal coverings on researched solid surfaces which interact with liquid metal with exothermic effect, allow to simulate conditions of space vacuum. Influence of vacuum was revealed at wetting of oxides by Cu—Ti alloys at 1200 °С. In vacuum 1×10^-2 Pa the threshold of wetting was observed—the angle practically did not change at increase in concentration up to 8—10% (at.) titanium.