In the present work the interfacial phenomena observed when an Al-Ti-B master alloy is produced have been studied using a modified sessile drop technique.The effect of emulsification has been demonstrated and the influence of small levels of CaF2 and MgF2 seen. The Al-Ti-B master alloys were made by the addition of potassium fluotitanate, K2TiF6, and potassium fluoborate, KBF4, to molten aluminium at 750°C. The product was an Al-5Ti-1B(wt-%) master alloy and a KF-AlF3 flux of eutectic composition. Problems can occur with the production of such alloys by first, emulsification of the liquid Al-Ti-B alloy and KF-AlF3 flux and second, agglomeration of titanium diboride particles by the wetting and engulfment of the KF-AlF3 flux. It has been found that levels of CaF2 and MgF2 in the fluoride salts greater than 50 ppm and 70 ppm, respectively, can prevent the above emulsification and boride agglomeration occurring.