Abstract
The influence of wettability between molten metal and mold materials on fluidity has been studied using glass and Teflon fine tubes/aqua-solutions system. For the discussion of work of adhesion and external pressure at the tip of flow on fluidity, flow rates were measured in laminar flow conditions. Flow was induced by the suction of solution with reduced pressure. The flow rate was calculated from images of a high speed video recorder. The inside diameter of the tubes was changed from 1.8mm to 4.0mm. The contact angle (wettability) was changed by the combination of tube materials and addition of a surfactant into pure water.
The flow rate in the wetting system (water/glass tube system) was higher than that of the non-wetting system (water/Teflon tube one) due to the external pressure caused by interfacial energy, namely the contact angles and surface tension. These results indicate that the influence of the work of adhesion is considerably weaker than that of external pressure.
