EVALUATION OF WETTABILITY OF MOLTON METAL BY UTILIZING MICROGRAVITY ENVIRONMENT

PROBLEM TO BE SOLVED: To carry out quantitative evaluation of wettability without requiring measurement of the contact angle and the surface tensile force by measuring the shapes of a single molton metal kept still on a substrate under a normal gravity and a micro gravity and measuring the wettability from the alteration of the shapes of the molton metal under the normal gravity and the micro gravity. SOLUTION: A molton metal has an approximately elliptical shape under a normal gravity and has an approximately spherical shape under a micro gravity. In this case, the contact point of the molton metal and the substrate moves and the interface surface area of the molton metal and the substrate is decreased. The work lost in the decrement of the interface surface area is adhesion work and corresponds to the potential energy lost of the molton metal when the gravity is changed from the normal gravity to the micro gravity. As long as the liquid shapes of the molton metal put on the substrate can precisely be recorded, any types of image recording apparatuses such as a camera and a video camera may be employed.