alloy was very similar to that of the 90 copper-10 nickel alloy at the 

 6,000 foot depth. The corrosion rate in the bottom sediment after 123 

 days at the 6,000 foot depth was lower than that in the sea water but 

 after 1064 days, the rates were the same. The corrosion rates at the 

 2,500 foot depth were lower than those at the 6,000 foot depth and 

 those in the bottom sediments were lower than those in the sea water. 

 The corrosion rates at depths of 4,250 and 4,500 feet in the Atlantic 

 Ocean, Reference 13, were lower than those in sea water at the 6,000 

 foot depth in the Pacific Ocean and decreased with increasing time of 

 exposure. The corrosion rate at the surface in the Pacific Ocean at 

 Point Mugu were lower than those in sea water at both depths. At the 

 surface in the Pacific Ocean at the Panama Canal Zone, the corrosion 

 rates also were less than in the sea water at both depths. Reference 16. 

 The corrosion of this alloy was uniform with the surfaces of the speci- 

 mens being covered with light green, flaky corrosion products. 



The corrosion rates of 70 copper-30 nickel alloy containing 5 per- 

 cent iron were very low as shown in Figure 37. They were the same in 

 the bottom sediments as in the sea water at both depths, 2,500 and 

 6,000 feet. The corrosion rates at the 6,000 foot depth increased 

 between 403 and 751 days of exposure. This increase is attributed to 

 the change in the protective film on this alloy. Through 400 days of 

 exposure at both depths the specimens were protected by a thin, hard, 

 black shiny film which deteriorated during longer exposure time causing 

 crevice corrosion and pitting with some selective attack (coppering). 

 There were copious deposits of copper on the specimens, especially in 

 pits and at faying surfaces. The corrosion rate at the surface after 

 181 days of exposure in the Pacific Ocean at Point Mugu was considerably 

 higher than at either depth and the alloy was attacked by crevice cor- 

 rosion to a depth of 5 mils. At a depth of 4,250 feet in the Atlantic 

 Ocean, Reference 13, this alloy corroded at a higher rate than at 

 either depth in the Pacific Ocean but at the same rate as at the surface 

 in the Pacific Ocean. 



The corrosion rates of the three copper-nickel alloys (90-10, 70-30 

 with 0.57o Fe, and 70-30 with 57„ Fe) are plotted in Figure 38 to show 

 that at the 6,000 foot depth the corrosion rates of the 90 copper-10 

 nickel and 70 copper-30 nickel with 0.57o Fe are comparable both in the 

 sea water and bottom sediments with the rates in the bottom sediments 

 being just below those in the sea water. At the 2,500 foot depth, the 

 corrosion rates in the sea water were comparable with those in the 

 bottom sediments at the 6,000 foot depth while those in the bottom sedi- 

 ments at the 2,500 foot depth were lower than those in the sea water. 

 The corrosion rates of the 70 copper-30 nickel with 5°L Fe were lower 

 than those of the other two alloys at both depths in sea water and in 

 the bottom sediments except in the sea water at the 6,000 foot depth 

 after 751 days of exposure. In this case, the corrosion rate was about 

 the same as the other two alloys. 



The corrosion of 95 copper-5 nickel was uniform, the corrosion 



15 



