CORROSION OF MATERIALS IN HYDROSPACE 



PART IV - COPPER AND COPPER ALLOYS 



Technical Note N- 961 



Y-F015-21-05-001 



by 



Fred M. Reinhart 



ABSTRACT 



A total of 1050 specimens of 45 different copper alloys were ex- 

 posed at two depths, 2,500 and 6,000 feet, in the Pacific Ocean for 

 periods of time varying from 123 to 1064 days in order to determine 

 the effects of deep ocean environments on their corrosion resistance. 



Corrosion rates, types of corrosion, pit depths, stress corrosion 

 cracking resistance, changes in mechanical properties and analyses of 

 corrosion products of the alloys are presented. 



Copper, beryllium-copper, arsenical admiralty brass, aluminum 

 brass, nickel brass, G bronze, modified G bronze, M bronze, leaded tin 

 bronze, phosphorous bronze A, phosphorous bronze D, nickel-aluminum 

 bronzes, Ni-Vee bronze A, Ni-Vee bronze B, Ni-Vee bronze C, copper- 

 nickel alloys 95-5, 80-20, 70-30 containing 0.5 percent iron, 70-30 

 containing 5 percent iron, 55-45, nickel-silver containing 18 percent 

 nickel, and Cu-Ni-Zn-Pb corroded uniformly and th^ir corrosion rates ;-^ 

 were low, 1 MPY or less after 1 year at a depth of 2,500 feet and 

 after 2 years at a depth of 6,000 feet. 



The remainder of the alloys were attacked by selective corrosion: 

 commercial bronze, red brass, yellow brass, Muntz metal, Naval brass, 

 manganese bronze, nickel-manganese bronze, wrought 5 and 7 percent 

 aluminum bronzes, cast 10, 11 and 13 percent aluminum bronzes, 3 per- 

 cent silicon bronze and silicon bronze A. 



The copper alloys were not susceptible to stress corrosion crack- 

 ing. 



Only the mechanical properties of the alloys attacked by selective 

 corrosion were adversely affected. 



The corrosion products consisted of cupric chloride, copper 

 hydroxide-chloride, metallic copper, copper oxy-chloride and nickel 

 hydroxide. 



