The differentiation of solid planets with segregation of metal from silicates happens during the Hadean time while the planet is still growing by accretion. The separation of metal occurs when at least the metallic phase is liquid and proceeds by a combination of transport by diapiric instabilities and by more diffuse percolation flow.
In this paper we develop a formalism derived from Bercovici et al. that can handle simultaneously two components, silicates and metal, and where the metal can be present both in solid and liquid states