PHASE-COMPOSITION OF FE-CONTAINING LANGMUIR-BLODGETT LAYERS AFTER THERMAL-TREATMENT IN A REACTIVE ATMOSPHERE

By the Langmuir-Blodgett technique, mono- and multilayers of ferric stearate were drawn onto silicon wafers. They were thermodesorbed in air at 250-300-degrees-C, and the layers formed in this way were found to consist of gamma-FeOOH with defective stoichiometry. By heating in H-2, the layers can be reduced to Fe2+ and even to alpha-Fe. The latter is magnetically ordered and highly corrosion resistant. Chloride ions, however, induce fast corrosion. FeCl2, formed by this corrosion, is rather unstable and transforms to an Fe3+ phase. The high corrosion resistance of the metallic Fe layer is assumed to be due to its excellent homogeneity. The experiments were performed using XPS, AES, CEMS, and SEM.