The formation of Zn4SO4(OH)6·4H2O in a rural atmosphere

Abstract

A field exposure program has been implemented in a rural atmosphere with emphasis on short exposure periods and detailed characterization of layers of corrosion products initially formed on zinc by means of a multi-analytical approach. Surface and bulk analytical studies in combination with deposition and climatic measurements have made it possible to identify a reaction path sequence on sheltered and unsheltered zinc panels, which is consistent with all methods used. It involves the formation of two structurally related phases, namely zinc hydroxycarbonate (Zn5(CO3)2(OH)6) as the initial phase and zinc hydroxysulfate (Zn4SO4(OH)6 · 4H2O) as the final phase on sheltered panels and (Zn5(CO3)2(OH)6) as the final phase on unsheltered panels. © 1994.