Wettability of Solid-Liquid Interface under Microgravity (Dynamic Behavior of Interface in Space)

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In the fabrication of metal-ceramic joint and composite materials, the wettability behavior must be considered to solve the interface phemomena. Especially, the further studies about the gravity is required to carry out the material experiments in space. Recently, many experimental procedures and analysis have been proposed and tried about the wettability, but a large part of methods have been operated only about the static condition without the bravityeffects. As these tests were made without some expeimetal conditions (dynamic condition, hysteresis, gravity ect.), the results had much difference and a few reproducibility among each tests. In order to observe the wettability in ground and space with considering the some experimental conditions, we proposed some new experimental methods and made the apparatus.In this paper, I carried out the Growing Drop Method and Liquid Bridge Methods in space using an aircraftflyingparabollic ballictic trajectories and added Meniscogrph Method, Incl … More ined Plate and Parallel Plate methods on ground. The results were compared each other and it investigated that the effects of gravity on the wettability.The following conclusions were obtained :(1) Growing Drop Method. Contact angle was depended on the drop size at static condition. Advancing and receding contact angle was affected on growing speed. Wetting behaviors varied with a gravity level.(2) Liquid Bridge Method. Liquid bridge shapes varied with the bridge aspect ratio and wettability onsolid-liquid interface. Contact angle at stable condition depended on the gravity level.(3) Meniscograph Method. Dynamic wetting behaviors were analyzed with a thoritical fluid mechanic equations and depended on the immersion speed, viscosity and the hysteresis. Oxidation had an effect considerably on the wetting phenomena using the melting metal.(4) Inclined Plate and Parallel Plate Method. The static contact angle can be evaluated from tase methods but there were some difference with another research results.(5) Comparing the results of each methods. On the ground, the static contact angle values were almost same between growing drop method and Meniscograph method and the liquid bridge's result agree with the reducing contact angle for other method. Under microgravity, the static contact angle values became larger than another reducing contact angle values at the liquid bridge method. Less