Analysis of Corrosion Products 



Analysis of corrosion products removed from various array components 

 identified their major constituents to be as follows. 



1. from 70-30 Cupro-nickel hydrophone cases: Ni(OH) , CuCI 



2. from 90-10 Cupro-nickel hydrophone cases: Ni(OH) , CuCI , CuO 



3. red material from aluminum tracking arm section: Metallic Cu, 

 Cu 0, amorphous A1 -XH 0, NaCI , Metallic Al 



4. Corrosion products from monel bands: CuC1„, CuO, Ni (OH) 



RESULTS OF INSPECTION, SAMPLE EVALUATION, AND RECOMMENDATIONS 



Considering the duration of exposure, the array was in remarkably 

 good condition. Except for the corrosion of the armor wires of the 

 electromechanical cable at the terminations, the galvanic corrosion 

 between the aluminum tracking arm sections and the hydrophone cases, the 

 corrosion of the aluminum tracking arm sections due to copper ion 

 contamination, and the crevice corrosion of the monel bands on the 

 hydrophone boots there was little significant corrosion of the array. 

 The aforementioned corrosion problems can be avoided by changes in future 

 designs. 



The electromechanical cable terminations can be augmented with 

 flexible boots to retain the corrosion preventive compound in the critical 

 area where the protective jacketing is removed from the wires. The 

 galvanic corrosion between the hydrophone cases and the aluminum tracking 

 arm section can be eliminated by electrical isolation such as that used 

 in the steel /aluminum joint on the tracking arm assembly. The copper 

 ion contamination- caused corrosion of the aluminum tracking arm sections 

 can be avoided by eliminating heavy metal (copper, mercury) antifoulants 

 from the vicinity of bare aluminum structures. The antifoulants are not 

 generally needed in the deep ocean to prevent the heavy accumulation of 

 fouling organisms normally encountered in shallow ocean environments. 

 The crevice corrosion of the monel bands can be reliably eliminated 

 either by selection of an alternate material resistant to crevice 

 corrosion or by cathodic protection of the monel bands. 



EVALUATION OF GUIDELINES FOR INSPECTION OF OBJECTS 

 RECOVERED FROM THE SEA 



The interim guidelines for inspection of objects recovered from the 

 sea (Appendix A) were found to be technically applicable to the evaluation 

 of the AUTEC array. The guidelines were useful in explaining to the 

 recovery team what was planned for the inspection and for giving personnel 

 assisting in the inspection an overview of the procedures to be used. 



