Microsensor for impact of molten metal microdrops

A microsensor has been developed to measure the spreading of molten metal microdrops upon impact with a solid surface with a time resolution below 1 mus. The sensor consists of fine conducting lines made of a gold (An) and titanium (Ti) two-layered structure on an insulating surface. The spreading of molten metal on the sensor leads to a resistance drop, which is converted to diameter evolution. Its measurements are made with a digital oscilloscope, which is much faster than state-of-the-art visualization systems. This work demonstrates the ultrafast sensing capability with a molten tin (Sn) microdrop. The sensor is especially useful for measuring the rapid expansion of the contact area in the very early stages of impact, which determines the degree of splashing. (C) 2004 Elsevier B.V. All rights reserved.