SURFACE-TENSION OF LIQUID CARBON SATURATE D FE-NI ALLOYS AND THEIR WETTABILITY TO SOLID GRAPHITE

Wetting of a solid graphite by carbon saturated Fe-Ni liquid alloys wa s studied by the sessile drop method at 1623 K. The results are summar ized 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 met al-graphite interface, is higher than that of the receding state, name ly the hysteresis of wetting. (3) The advancing contact angle is the s ame as that observed when the liquid alloy at carbon saturation was dr opped on the graphite substrate, while the receding one is close to th e value obtained when the carbon-free liquid was melted on the graphit e substrate. (4) The difference between the advancing and receding con tact angles was discussed by Aksay's model.