CORROSION OF MTERIALS IN HYDROSPACE. PART II - NICKEL AND 



NICKEL ALLOYS 



Technical Note N-9I5 



Y-F015-01-05-002A 



by 



Fred M. Reinhart 



ABSTRACT 



A total of 535 specimens of 75 different nickel alloys were 

 exposed at two different depths in the Pacific Ocean for periods of 

 time varying from 123 to 1064 days to determine the effects of deep 

 ocean environments on their corrosion resistance. 



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

 welding, stress corrosion cracking resistance, changes in mechanical 

 properties and analyses of corrosion products of the alloys are 

 presented. 



Of those alloys tested, the following were practically immune 

 to corrosion: nickel-chromium- iron alloy 718; nickel-iron-chromium 

 alloys, except 902; nickel-chromium-molybdenum alloys; nickel-cobalt- 

 chromium alloy; nickel-chromium- iron-molybdenum alloys; nickel- 

 chromium-cobalt alloy; and nickel-molybdenum-chromium alloy. Alloys 

 attacked by uniform or general corrosion were the cast nickel-copper 

 alloys; nickel-molybdenum- iron alloy; and nickel-molybdenum alloy. 

 Alloys attacked by crevice or pitting corrosion were the nickels; 

 wrought nickel-copper alloys; nickel-chromium- iron alloys except 718; 

 nickel- iron-chromium alloy 902; nickel-tin-zinc alloy; nickel-beryllium 

 alloy; nickel-chromium alloys; and nickel-silicon alloy. 



Corrosion resistance of welds in the nickel alloys depends upon 

 the selection of the proper welding electrodes. The nickel alloys 

 were not susceptible to stress corrosion cracking. Corrosion pro- 

 ducts consisted of oxides, hydroxides, chlorides and oxychlorides. 

 Mechanical properties of the alloys were not adversely affected in 

 a significant way. 



