Anode, tensile test

Edwards e/a/. carried out controlled potential, slow strain-rate tests on Zimaloy (a cobalt-chromium-molybdenum implant alloy) in Ringer s solution at 37°C and showed that hydrogen absorption may degrade the mechanical properties of the alloy. Potentials were controlled so that the tensile sample was either cathodic or anodic with respect to the metal s free corrosion potential. Hydrogen was generated on the sample surface when the specimen was cathodic, and dissolution of the sample was encouraged when the sample was anodic. The results of these controlled potential tests showed no susceptibility of this alloy to SCC at anodic potentials. 

The strengths of the Pb-Ag-Ca alloys were experimentally examined using tensile and Vickers hardness tests. The results were compared to the data for a conventional Pb-Ag alloy used as anode material for zinc electrowinning. 

Figure 7 Aspects of the nucleation of SCC by localized corrosion, (a) Peak aged Al-Li-Cu-Mg alloy 8090 after unstressed preexposure in aerated 3.5% NaCl for 7 days, (b) SCC initiated from one of the fissures shown in (a), following removal of the solution and continued exposure to laboratory air under a short transverse tensile stress (courtesy of J. G Craig, unpublished data), (c) Creviced region of 316L stainless steel after a slow strain rate test in 0.6M NaCl + 0.03M Na2S203 at 80°C and an applied anodic current of 25 xA, showing unstable pitting leading to crevice corrosion and SCC initiation (courtesy of M. I. Suleiman).

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