The anodic oxidation of copper in LiOH solution has been investigated by galvanostatic, potentiostatic, and voltammetric sweep techniques. The structure and composition of the films were determined by x-ray and electron diffraction, and by scanning electron microscopy. Cu(OH)2 forms in two layers: a base layer grown by a solid-state mechanism and an upper layer of individual crystals nucleated and grown from solution. The size and number of upper layer crystals are dependent on electrode potential. More anodic potentials produce a large number of randomly deposited crystals, whereas less anodic potentials result in fewer, more highly developed crystals. Increased stirring results in a greater loss of material into solution, and in the extreme, nucleation and growth are completely prevented. For sufficiently low crystallization rates, produced galvanostatically, the thermodynamically stable phase, CuO, is formed. At higher rates the formation of Cu(OH)2 dominates. A nucleation and growth mechanism is given and discussed with reference to other metal systems. ExperimentalMeasurements were made on copper electrodes (99.99% purity) of 5.0 cm 2 geometric surface area. Rotating disk experiments were made on 2.5 cm 2 copper disks embedded in Teflon. Samples were polished

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The surface of Monel‐400 alloy was exposed to high pH, aqueous corrosion at 285°C, under both oxidizing and reducing conditions. After exposures lasting from 0.3 to 335 hr the surfaces were examined by x‐ray photoelectron spectroscopy, scanning electron microscopy, and other techniques. Under reducing conditions, no corrosion film forms on the metal surface, but under oxidizing conditions, the first corrosion layer which forms at the solution interface is entirely normalNifalse(OH)2 . This hydroxide, which persists for long times at pH∼10 but which rapidly converts to normalNiO at pH∼14 , is shown to result from a precipitation process. The composition of the corrosion film is determined by the relative solubilities of nickel and copper at the interface. A composition profile of the corrosion layer beneath the outermost film shows a gradual increase in cuprous ion concentration with increasing depth, probably due to solid‐state migration. This suggests that the aqueous corrosion of Monel‐400 involves both solid‐state oxide growth and an ionic dissolution and precipitation mechanism.

Table IlL Coefficients of the polynomial for A~SH E (7")* --~Eobs (Eq. [ii]) as a function of KCI concentration (M) EXTERNAL REFERENCE ELECTRODES M port of this work under Contract No. RP-1168-1.