Abstract
Under microgravity conditions, interdiffusion experiments of molten Au-Ag alloy system were undertaken. The diffusion in the flight specimens was faster than that in the ground ones, and their concentration curves deviated from theoretical ones, extraordinarily. These results may be ascribed to Marangoni convection flow, which became dominant under microgravity conditions in place of the gravitational convection one. It may be caused by the existence of free surface and a very large concentration gradient at the interface of the diffusioncouple type of specimen. The suppression of free surface formation and consideration for the wettability between molten alloy and crucible material will be indispensable.
