Unusual Corrosion Growth Products Formed on Copper

An electron transmission study was made of the corrosion growth products formed on preworked and preannealed copper at various temperatures in environments of water vapor saturated air and oxygenated water vapor saturated air. Unusual blade-type growths were obtained only on the preworked specimens exposed to water vapor saturated air and within a narrow critical temperature range. These results indicate that blade-type formations are a unique transition growth phenomenon dependent to a large extent on the presence of the water vapor and the stresses induced during preworking. Oxygen enrichment of the reacting atmosphere accentuated whiskertype growths for both the preworked and preannealed samples. At some temperatures in the oxygen enriched water vapor atmosphere the preannealed samples exhibited increasd growth over that typified by the preworked samples. In some cases whiskers with bulbous masses at the tips were observed, suggesting melting at the tips from the heat generated by the electron beam. 3.4.3, 6.3.6