Accession Number : AD0727221

Title :   Anaerobic Bacterial Corrosion of Metals in Sea Water at Elevated Hydrostatic Pressures.

Descriptive Note : Final rept. 1 May 68-31 May 71,

Corporate Author : CLAPP (WILLIAM F) LABS INC DUXBURY MASS

Personal Author(s) : Willingham,Charles A.

Report Date : 31 JUL 1971

Pagination or Media Count : 30

Abstract : The effects of hydrostatic pressures on the anaerobic corrosion of ingot iron, E.C. Grade aluminum, and 316-type stainless steel by three marine sulfate-reducing bacterial cultures were examined. Depending upon the period of exposure, all three cultures were capable of producing a greater amount of iron corrosion at 200 atmospheres than at one atmosphere. At 20 C, all cultures were sterilized by a hydrostatic pressure of 600 atmospheres, although incubation of one culture (BS-1) at 40 degrees allowed limited growth and corrosion of iron at this pressure. Increase in tha amount of available nutrient medium in a compatable pressure system produced a significant increase in the corrosion of iron. Weight loss of aluminum and stainless steel specimens was little effected by the presence of a bacterial system. Agressiveness of all three cultures to iron at one and 200 atmospheres when molecular hydrogen was present in the bacterial/metal system was significantly reduced. Little change in any corrosion of aluminum or stainless steel was noted when also exposed to a system with hydrogen. Interaction of the hydrogen present in the culture medium with the iron surface to produce sufficient atomic hydrogen for bacterial metabolism was indicated as the cause of unusually low corrosion rates but good bacterial growth. Type of corrosion attack on iron was most often uniform; when corrosion of aluminum or stainless steel occurred, attack was a shallow, pitting type. No intergranular cracking type of corrosion was observed. (Author)

Descriptors :   (*CORROSION, BACTERIA), HYDROSTATIC PRESSURE, SEA WATER, MARINE BIOLOGY, MICROBIOLOGY, IRON, ALUMINUM, STAINLESS STEEL

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE