Non-galvanic mass transport in molten fluoride salt isothermal corrosion cells

Potentiodynamic Polarization of Pure Metals and Alloys in Molten LiF-NaF-KF (FLiNaK) Using the K/K+ Dynamic Reference Electrode

“…Selective dissolution of Cr is frequently observed. [37][38][39] The tendency for Fe and Cr to be corroded simultaneously is consistent with recent observations of Fe-based alloy corrosion in FLiNaK conducted in static corrosion tests 40,41 and in non-isothermal thermal convection flow tests. 42 A few studies have shown varying levels of preferential dissolution of Cr in 316 stainless steel when the chemistry of the salt was modified.…”

Integrated High‐Throughput and Machine Learning Methods to Accelerate Discovery of Molten Salt Corrosion‐Resistant Alloys

“…For alloy #5, alloy #7, alloy #17, and alloy #20, three EDS line scans were conducted at different locations of each sample, the final depletion depth was defined based on the average value of the depletion depths obtained from the three EDS line scans and the standard deviation was used as the error bar as shown in Figure 4a. Previous study directly comparing the element variation depths of two Ni-201 alloy at the same experiment condition measured by GDOES and EDS had shown similar results from both techniques, [17] therefore, validating both techniques for determining the corrosion resistance of additive manufactured alloys in this study. However, it still needs to be noted that GDOES sputtered area included tens of thousands of grains such that the depletion depth measured by GDOES was a convolution of uniform and localized corrosion, if any.…”

“…A similar phenomenon also appeared on the post-corrosion Ni-201 alloy as reported in a previous study. [17] However, in the present study, the extent and 2𝜃 location of peak splitting were found to vary among the different printed alloys (see XRD patterns of all other post-corrosion printed alloys in Figure S8, Supporting Information). The peak splitting is likely a result of the change in lattice parameter at the near surface region, induced by the changes in composition of the FCC phase (depletion of elements, and injection of vacancies).…”

Activity gradient driven mass transport in molten fluoride salt medium

“…One of the most common methods for materials degradation screening studies in salt environments has been the use of static isothermal corrosion test cells 6,7 , where sample material is submerged in static salt and held at a constant test temperature for a predetermined amount of time. However, these types of isothermal testing environments, although relatively simple in design, can create unique challenges that may affect the corrosion rates and mechanisms driving corrosion.…”

“…Because galvanic contact could influence the materials' corrosion rate, studies have used a ceramic strip to electrically isolate the two materials to effectively eliminate the galvanic couple 12,13 . Recent work, however, has shown that even when the galvanic coupling is eliminated, dissimilar materials still interact with one another with the occurrence of significant mass transport 7,14 . This effect, although not clearly identified, has been hypothesized to be driven by an activity gradient between dissimilar materials and not electrical contact.…”