INTRODUCTION 



The development of deep diving submarines which can stay sub- 

 merged for long periods of time has focused attention on the deep 

 ocean as an operating environment. This has created a need for 

 information concerning the behavior of common materials of construc- 

 tion as well as newly developed materials with promising potentials, 

 at depths in the ocean. 



To study the problems of construction in the deep ocean, project 

 "Deep Ocean Studies" was established. Fundamental to the design, 

 construction and operation of structures, and their related facilities 

 is information with regard to the deterioration of materials in deep 

 ocean environments. This report is devoted to the portion of the 

 project concerned with determining the effects of these environments 

 on the corrosion of metals and alloys. 



The test sites for the deep ocean exposures are shown in Figure 

 1 and their specific geographical locations are given in Table 1. 

 The complete oceanographic data at these sites, obtained from NCEL 

 cruises between 1961 and 1967, are summarized in Figure 2. Initially, 

 it was decided to utilize the site at the 6,000 foot depth. Because 

 of the minimum oxygen concentration zone found between the 2,000 and 

 3,000 foot depths, during the early oceanographic cruises, it was 

 decided to establish a second exposure site (STU II-l and II-2) at a 

 nominal depth of 2,500 feet. For comparative purposes, the surface 

 water site V was included. 



A summary of the characteristics of the bottom waters 10 feet 

 above the bottom sediments at the two deep ocean exposure sites and 

 at the surface exposure site is given in Table 1. 



Sources of information pertaining to the biological character- 

 istics of the bottom sediments, biological deterioration of materials, 

 detailed oceanographic data, and construction, emplacement and 

 retrieval of STU structures are given in Reference 1. 



The procedures for the preparation of the specimens for exposure 

 and for evaluating them after exposure are described in Reference 2. 



Previous reports pertaining to the performance of materials in 

 the deep ocean environments are given in References 1 through 7. 



This report is a discussion of the results obtained of the 

 corrosion of titanium and titanium alloys for the six exposure periods 

 shown in Table 1 and for 181 days of exposure five feet below the 

 surface. 



