Surface Tension of Liquid Carbon Saturated Fe-Ni Alloys and Their Wettability to Solid Graphite

Wetting of a solid graphite by carbon saturated Fe-Ni liquid alloys was studied by the sessile drop method at 1623 K. The results are summarized as follows, (1) Surface tension of the liquid alloys was 1720±40 mN/m which showed no composition dependence. (2) It was found that the advancing contact angle, which was measured by increasing the metal-graphite interface, is higher than that of the receding state, namely the hysteresis of wetting. (3) The advancing contact angle is the same as that observed when the liquid alloy at carbon saturation was dropped on the graphite substrate, while the receding one is close to the value obtained when the carbon-free liquid was melted on the graphite substrate. (4) The difference between the advancing and receding contact angles was discussed by Aksay’s model.