The initial corrosion behavior of nickel exposed under sheltered conditions in a rural atmosphere has been investi gated using two starting dates in April and October. Emphasis has been placed upon short-term exposure periods from 1 day to 4 months but longer exposure periods up to 1.5 years have also been included. A multianalytical approach has been used to characterize the corrosion products, which have resulted in a coherent picture with respect to both surface composition and morphology Within hours of exposure, a thin film of NiO and Ni(OH)(2) is observed on the freshly polished nickel surface. After a few days, independent of starting date, sulfate-containing corrosion products are formed with characteristic dendritic morphology. The sulfate-containing corrosion products grow laterally and cover 25 to 30% of the nickel surface after 120 days of exposure. Promoted by initial dry and wet periods and by increased concentrations of sulfate particulates, the formation of sulfate-containing corrosion products is faster in April than in October. After 1 year of exposure, the composition is NiSO4 . 6H(2)O.