Wiktionary
interdiffusion
n. The mutual diffusion of two fluids, especially through a membrane
Usage examples of "interdiffusion".
The verbal outpouring was to be on “The Interdiffusion of Molybdenum by the Renwick Process,” and its delivery was scheduled for the Regal Room of the Park-Ritz Hotel, where the cheapest room, even in depression times, was seven dollars a night.