The mechanical properties of copper and beryllium- copper were not 

 adversely affected by exposure at depth in the Pacific Ocean for periods 

 of time of up to 2 years. 



Copper-Zinc Alloys (Brasses) 



Except for Muntz metal and manganese bronze the copper-zinc alloys 

 corroded at rates which decreased asymptotically with increasing dur- 

 ation of exposure both in sea water and in the bottom sediments at the 

 6,000 foot depth. After 35 months of exposure the corrosion rates were 

 between 0.2 and 0.8 MPY. At the 2,500 foot depth the corrosion rates 

 in sea water were about the same as at the 6,000 foot depth but in the 

 bottom sediments at 2,500 feet the rates were lower than in the sea 

 water at 2,500 feet and in the bottom sediments at 6,000 feet. The 

 non- conformity of Muntz metal and manganese bronze with the behavior 

 of the other copper-zinc alloys is attributed to the dezincif ication of 

 these two alloys. 



Commercial bronze, red brass, commercial brass, yellow brass, 

 Muntz metal, Naval brass, Tobin bronze, manganese bronze and nickel- 

 manganese bronze were dezincif ied while arsenical admiralty brass, 

 aluminum brass and nickel brass were not dezincif ied. 



Most of the copper-zinc alloys corroded at faster rates at the 

 surface in the Pacific Ocean at Point Mugu than at depth. Commercial 

 bronze and Naval brass corroded at slower rates, Muntz metal at a 

 faster rate, and manganese bronze at the same rate at depth as at the 

 surface in the Pacific Ocean at the Panama Canal Zone. 



Arsenical admiralty brass and Muntz metal were not susceptible to 

 stress corrosion cracking at depth in the Pacific Ocean. 



The mechanical properties of arsenical admiralty brass were not 

 adversely affected by exposure at depth in the Pacific Ocean while 

 those of Muntz metal and nickel-manganese bronze were adversely 

 affected. 



Corrosion products consisted of cupric chloride (Cu CI2) , copper 

 hydroxy-chloride (Cu2(0H)3Cl) and metallic copper, 36 percent. 



Bronzes 



Except for the silicon bronzes, the bronzes corroded essentially 

 at constant rates with increasing duration of exposure both in sea 

 water and in the bottom sediments at depths of 2,500 and 6,000 feet in 

 the Pacific Ocean. The corrosion rates of the silicon bronzes initially 

 were higher than the other bronzes but after 35 months of exposure at 

 the 6,000 foot depth they were comparable with the other bronzes. The 

 corrosion rates of the bronzes were higher at the surface in the Pacific 

 Ocean at Point Mugu than at depth. 



The corrosion rate of phosphor bronze A was higher at the surface 

 in the Pacific Ocean at the Panama Canal Zone and in Port Hueneme 

 Harbor than at depth while those for silicon bronze and 5 percent and 



19 



