Galvanic Corrosion

Galvanic corrosion is an electrochemical reaction in which one metal corrodes preferentially when in electrical contact with a different type of metal and both metals are immersed in an electrolyte. When two or more different kinds of metals come into contact in the presence of an electrolyte a galvanic couple is set up as different metals have different electrode potentials. The electrolyte provides a mode for ion migration whereby metallic ions can move from the anode to the cathode. This leads to the anodic metal corroding more quickly than it otherwise would; the corrosion of the cathodic metal is reduced. This section contains reports related to galvanic corrosion.

Select Report to read more     Electrochemical Testing of Drill Collar Alloys Galvanic corrosion measurements were conducted (ASTM G-71) between drill collar and shock sleeve alloys and cyclic potentiodynamic polarization scans (ASTM G-61) on drill collar alloys for the determination of susceptibility to localized corrosion in simulated drilling fluid. The drill collar alloys selected for the program were (1) AG-17, (2) P550, (3) P530, (4) P530HS, (5) NMS 100, (6) SMF 166, (7) 15-15LC Modified, and (8) Staballoy 734, and the shock sleeve alloys chosen were Spinodal (CDA ...   Read more         This report is available for download to corporate users only at this time and will be soon made available for individual purchase. Galvanic Corrosion of Nitrided Materials Coupons of nitrided and non-nitrided 9Cr and 13Cr were exposed to a simulated downhole environment (250 F, 200 psia CO2, 1 psia H2; aqueous phase of 5 percent NaCl). Coupons were fixtured in a static autoclave such that galvanic effects between sets of coupons could be determined. One group of 16 coupons was exposed to the vapor phase of the autoclave and 1 group of sixteen coupons was exposed to the liquid phase. Vapor phase corrosion was found to be minimal from the standpoint of weight loss....   Read more         This report is available for download to corporate users only at this time and will be soon made available for individual purchase. Galvanic Corrosion of Drill Collar Alloys Galvanic corrosion occurs when two dissimilar materials in electrical contact are simultaneously exposed to a corrosive fluid. In general, the more active alloy of the couple corrodes preferentially while the less active (more noble) material is cathodically protected. The rate of galvanic corrosion is a function of several variables including area ratios, corrosivity of the medium, temperature, fluid velocity, nature of the materials, etc.   Read more         This report is available for download to corporate users only at this time and will be soon made available for individual purchase. Engineering Database On Galvanic Corrosion In Oil And Gas Production Comprehensive data on corrosion tests for various materials and environments.   Read more         This report is available for download to corporate users only at this time and will be soon made available for individual purchase.