International Nickel Company, Incorporated. Permission for their 

 incorporation in this report has been granted by Dr. T. P. May, Manager. 

 Harbor Island (Kure Beach) Corrosion Laboratory, Wrightsville Beach, 

 North Carolina, Reference 9. 



Results from other participants in the NCEL exposures are also in- 

 cluded; Annapolis Division, Naval Ship Research and Development Center 

 (formerly Marine Engineering Laboratory) (Reference 10) and the 

 Chemistry Division, NCEL, (Reference 11). 



Deep ocean corrosion results from the Atlantic Ocean (References 

 12 and 13), surface corrosion data from the Atlantic Ocean (Reference 

 14) and surface corrosion data from the Pacific Ocean (References 15 

 and 16) are included for comparison purposes. 



COPPER 



The chemical composition of the coppers are given in Table 2, 

 their corrosion rates and types of corrosion in Table 3, their re- 

 sistance to stress corrosion cracking in Table 4, and changes in their 

 mechanical properties due to corrosion in Table 5. 



Corrosion 



The excellent corrosion resistance of copper is partially due to 

 its being a relatively noble metal. However, in many environments its 

 satisfactory performance depends on the formation of adherent, relative- 

 ly thin films of corrosion products. In sea water corrosion, resist- 

 ance depends on the presence of a surface oxide film through which 

 oxygen must diffuse in order for corrosion to continue. This oxide 

 film adjoining the metal is cuprous oxide covered with a mixture of 

 cupric oxy-chloride, cupric hydroxide, basic cupric carbonate and 

 calcium sulfate. Since oxygen must diffuse through this film for 

 corrosion to occur it would be expected that under normal circumstances 

 the corrosion rate would decrease with increase in time of exposure. 



The corrosion rates of copper in sea water, both at depth and at 

 the surface, are given in Table 2 and shown in Figure 3. The corrosion 

 rate decreased with increase in duration of exposure at the 6,000 foot 

 depth in the Pacific Ocean and the data from all three participants. 

 Naval Civil Engineering Laboratory, International Nickel Company, Inc. 

 and Naval Ship Research and Development Center was in very good agree- 

 ment. At the 5,600 foot depth in the Atlantic Ocean, Reference 12, the 

 corrosion rate for copper after 1050 days of exposure was practically 

 the same as at the 6,000 foot depth in the Pacific Ocean. This close 

 agreement of the corrosion rates of copper in the two oceans is not 

 unexpected since the corrosion of copper is not appreciably affected by 

 changes in oxygen concentration. 



At depths of 4,250 and 4,500 feet in the Atlantic Ocean, Reference 



