The Marangoni convection is supposed to be an important phenomenon that significantly affects the solidification. For understanding the Marangoni convection mechanism, visualizing the convection phenomenon of molten tin with ultrasonic wave has been conducted. This paper reports development of a tracer material that is used in the molten tin for visualizing the convention by ultrasonic wave.
In this research, we have chosen vitreous hollow sphere with approximately 1 mm diameter, examined several plating processes, constructed the equipment of the plating process, and succeeded in coating the surface of vitreous hollow sphere with nickel. The particle obtained is a so-called micro metal balloon (MMB) that has spherical hollow structure with metallic luster. The composition of MMB was almost fixed in a weight ratio of Ni : P=84 : 16, the distribution of Ni thickness was sharp, and finally it was confirmed that the MMB was suitable for the tracer material.
