Visual Observations of Corrosion of Materials on Stu I-1 after 1064 Days of Exposure at a Depth of 5300 Feet in the Pacific Ocean

摘要

Visual observations of materials exposed on the bottom of the Pacific Ocean at a depth of 5300 feet for 1064 days showed that the corrosion of most of the alloys in the mud was different from the corrosion in the water 6 feet to 10 feet above the bottom. The stainless steels exhibited a honey-comb type of attack very similar to the type of attack by stagnant surface sea water. The 5000 series aluminum alloys showed deep pitting; this could be explained on the basis of the low oxygen content combined with the nearly stagnant condition of the sea water. The 70% Ni-30% Cu alloy which was partially embedded in the sediment showed pitting that undoubtedly was caused by the composition of the peculiar environment in the water-sediment interfacial zone. The plastic materials were unaffected except those portions encased in wood which were attacked by wood boring animals. Hydroids attached themselves to and grew on both metallic and nonmetallic materials with no apparent deteriorative effects.