IRRADIATION EFFECTS ON THE SURFACE REACTIONS OF METALS. Summary Report for October 1, 1958 to November 1, 1959

Abstract

Weight increases during the oxidation of irradiated foils of pure copper were greater than for unirraaiated specimens. Enhanced reactivity appeared to be strongest in the thin-film region up to about 5 mu g/cm/sub 2/. Oxide film (Cu/ sub 2/O) thickness for both irradiated and unirradiated specimens was approximately 1200 A. Radiation did not affect the reduction of Cu/sub 2/O during the induction period (period in which the reduction proceeds very slowly or not at all). In later stages of the reduction process, a serious lack of reproducibility was observed. Radiation effects on films of Cu/sub 2/O formed by prior oxidation of the copper substrate decreased the kinetics of secondary oxidation. The secondary oxidation curve exhibited a large gap at the point of interrnption for irradiation. The development of an automatic recording microbalance of high sensitivity and a furnace for studies in reactor radiation fields is reported. Measurements were made of the electrode potentials of irradiated (5.5 x 10/sup 19/ neutrons cm/sup -2/) copper, aluminum, magnesium, and zirconium. Cell potentials were found to be dominated by the oxide films formed on the electrode surfaces. The results indicate that radiation does affect the local anode reaction potential. No significant difference between the rates of the dissolution reaction of cold-worked and annealed copper specimens in Fe(NO/sub 3/)/sub 3/ was observed. Results on irradiated specimens indicated that irradiation enhanced the reactivity of copper specimens on the order of 5%. Irradiated copper specimens developed etch pits at a slightly greater rate than unirradiated specimens in