title: Coarsening of precipitation patterns in a moving reaction-diffusion front.
abstract: Precipitation patterns emerging in a two-dimensional moving front are investigated on the example of NaOH diffusing into a gel containing AlCl3 . The time evolution of the precipitate Al(OH)_{3} can be observed since the precipitate redissolves in the excess outer electrolyte NaOH and thus it exists only in a narrow optically accessible region of the reaction front. The patterns display self-similar coarsening with a characteristic length xi increasing with time as xi(t) approximately sqrt[t] . A theory based on the Cahn-Hilliard phase-separation dynamics, including redissolution, is shown to yield agreement with the experiments.
authors.affiliation: Department of Physics, University of Technology and Economics, 1521 Budapest, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Volford
authors.forename: I
authors.initials: I
authors.lastname: Lagzi
authors.forename: F
authors.initials: F
authors.lastname: Molnár
authors.forename: Z
authors.initials: Z
authors.lastname: Rácz