Mechanism of fluxing action for brazing titanium

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The cumulative weigt loss of titanium in melt fluxes was measured at 900ﾟC using (1) 100%LiF,(2) 100%KHF_2, (3) 70%KHF_2-30%LiF,(4) 50%KHF_2-50%LiF-, (5) 56%KHF_2-14%LiF30%NaCl・KCl, (6) 100%NaCl・KCl. The component of NaCl・KCl contained 50%NaCl and 50%KCl by weight. The element distribution in spreading of Ag solder on titanium with 50%KHF_2-50%LiF was analyzed by EPMA,after heating for 25,35,45, and 75sec at 800ﾟC.The results were as folows.1. The cumulative weigt loss of titanium increased with pssing times.2. The reactivity of fluxes increased in order of (6), (5), (4), (3), (2), (1).3. The degree of spreading of Ag solder did not always coincide with the reactivity of fluxes.4. The front of edge of spreading was rich in Cu and poor in Ag for all heating times.5. Solder near interface with Ti was rich in Cu and Ti for 25 and 35 sec heating.6. The upper part of solder inside the front of edge of spreading was rich in Ag and the lower part poor in Ag for 45 and 75sec heating, whereas the upper was poor in Ti and the lower part was rich in Ti.