Early stages of dissolutive spreading

The initial instants of spreading in high-temperature dissolutive systems (Cu and Au on Ni) are recorded using high-speed video and a drop transfer set-up. The results suggest the existence of an initial regime where the advance of the triple junction is too fast compared with dissolution and spreading occurs on a flat unreacted surface. The analysis indicates that spreading is then controlled by the triple-line friction. The calculated friction coefficients are similar to those for non-reactive high-temperature systems.