First corrosion stages in Tournemire claystone/steel interaction: In situ experiment and modelling approach

Long-term corrosion behaviour of carbon steel and stainless steel in Opalinus clay: influence of stepwise temperature increase

“…The mean average CR could not be determined, but can be estimated as significantly lower than that measured for Csteel. This behaviour is in agreement with previous studies of St-steel corrosion in clay environments [23,24], and the known effect of Cr in suppressing generalised corrosion in carbonate systems [25,26].…”

Stability of Clay Barriers Under Chemical Perturbations

“…The effect of the transition between oxic and anoxic conditions has also been investigated very recently in laboratory experiments (Ishidera et al, 2008;Jeannin et al, 2010Jeannin et al, , 2011El Hajj et al, 2013), in situ experiments (Gaudin et al, 2013), and archaeological analogs (Saheb et al, 2014). Interestingly, the mineral phases precipitating during the transient oxic phase tend to be destabilized and to form the corrosion products and secondary minerals similar to those observed in the anoxic phase (magnetite, ferrous carbonates, and 7Å Fe-rich phyllosilicates).…”

“…In integrated FIGURE 5.3 Electron microscopy in backscattered electron mode and corrosion products identified in the internal and external dense product layer (DPL) and in the transformed clay matrix layer (TML) after 2 years of iron corrosion in contact with clay-rock at 90 C . experiments however, the results were more diverse: no significant change in mineralogy and diffusion properties (Xia et al, 2005;Ishidera et al, 2008); no Mt transformation, CEC decrease, and permeability increase of up to two orders of magnitude (Carlson et al, 2007); no significant changes in mineralogy, no change in CEC but slight change in swelling pressure suggesting that the original Mt was transformed into iron-rich dioctahedral Sm (Gaudin et al, 2013;Milodowski et al, 2009).…”

“…The alteration zone extends to distance from 0.1 to 2 mm in integrated experiments in the average time frame of a year (Smart et al, 2006;Carlson et al, 2007;Ishidera et al, 2008;Schlegel et al, 2008;Milodowski et al, 2009) and in in situ experiments (after 6 years in Gaudin et al, 2013), and up to 3 mm in several hundred years old archaeological analogs (Neff et al, 2005(Neff et al, , 2006. Within this zone, physicochemical alteration is observed which may ultimately affect properties such as permeability, diffusivity, and CEC.…”