The behavior of a AgNO3/Ag2O/Ag "sandwich" upon heating in vacuum was studied by in situ X-ray photoelectron spectroscopy (XPS) and ex situ scanning electron microscopy (SEM). The AgNO3/Ag2O/Ag "sandwich" was prepared by exposure of a silver foil to a NO : O-2 mixture. The upper layer of the "sandwich" consists of AgNO3 crystals of a mean size between 0.1 and 0.4 mu m. Heating at 550 K in vacuum results in melting of the AgNO3 crystals. A liquid film of AgNO3, readily wetting the silver, covers the surface. Cooling below the melting point of AgNO3 leads to the agglomeration of silver nitrate to long islands with a size reaching a few tens of micrometers (mu m). The possible effects of AgNO3 liquid-phase formation on surface processes are discussed.