Wetting and Spreading Behavior of Liquid Si-Ti Eutectic Alloy in Contact with Glassy Carbon and SiC at T = 1450 °C

The contact heating (CH) sessile drop and capillary purification (CP) methods were applied for a fundamental study concerning the wettability and reactivity of liquid Si-16.2 at. pct Ti alloy (eutectic composition) in contact with glassy carbon (GC) and SiC at T = 1450 °C under an Ar atmosphere. Different spreading stages with different slopes, depending on the starting conditions of the materials used, where observed. On the contrary, the final contact angle value seemed not affected and the values of θ ≈ 44 deg ± 2 and θ ≈ 42 deg ± 2 where displayed on GC and SiC, respectively. The solidified Si-Ti eutectics/GC and Si-Ti eutectics/SiC samples were examined both at the top of the drop and at the cross section by scanning electron microscopy (SEM)/energy-dispersive spectroscopy (EDS). The presence of a SiC layer as unique reaction product at the Si-Ti eutectics/GC interface, confirmed that wettability is mainly driven by reactivity. Contrarily, as nonreactive system, at the Si-Ti eutectics/SiC interface a weak dissolution of SiC substrate was detected.