High-Throughput Electrochemistry to Study Materials Degradation in Extreme Environments.

Electrochemistry has been used for decades to study materials' degradation in situ in corrosive environments, whether it is in room-temperature chemically aggressive solutions containing halide ions or in high-temperature oxidizing media such as pressurized water, liquid metals, or molten salts. Thus, following the recent surge in high-throughput techniques in materials science, it seems quite natural that high-throughput electrochemistry is being considered to study materials' degradation in extreme environments, with the objective to reduce corrosion resistant alloy development time by orders of magnitude and identify complex degradation mechanisms. However, while there has been considerable interest in the development of high-throughput methods for accelerating the discovery of corrosion resistant materials in different environments, these extreme environments propose formidable and exciting challenges for high-throughput electrochemical instrumentation, characterization, and data analysis. It is the objective of this paper to highlight those challenges, to present relatively new efforts to tackle them, and to develop research perspectives on the future of this exciting field. This Perspective is articulated around four main interconnected topics, which must be conjointly considered to enable corrosion resistant alloy design using high-throughput electrochemical methods: (1) high-throughput processing methods to develop material libraries, (2) high-throughput electrochemical methods for corrosion testing and evaluation, (3) high-throughput machine-learning augmented electrochemical data analysis, and (4) high-throughput autonomous electrochemistry representing the future of accelerated electrochemistry research.

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

Insufficient availability of molten salt corrosion-resistant alloys severely limits the fruition of a variety of promising molten salt technologies that could otherwise have significant societal impacts. To accelerate alloy development for molten salt applications and develop fundamental understanding of corrosion in these environments, here an integrated approach is presented using a set of high-throughput (HTP) alloy synthesis, corrosion testing, and modeling coupled with automated characterization and machine learning. By using this approach, a broad range of CrFeMnNi alloys are evaluated for their corrosion resistances in molten salt simultaneously demonstrating that corrosion-resistant alloy development can be accelerated by 2 to 3 orders of magnitude. Based on the obtained results, a sacrificial protection mechanism is unveiled in the corrosion of CrFeMnNi alloys in molten salts which can be applied to protect the less unstable elements in the alloy from being depleted, and provided new insights on the design of high-temperature molten salt corrosion-resistant alloys.

In Situ Corrosion Monitoring of the T91 Alloy in a Molten Chloride Salt Using a Miniaturized Electrochemical Probe for High-Throughput Applications.

Corrosion sensing is essential to monitor and safeguard materials' health in molten salts. The present study developed a three-electrode-array minisensor for high-temperature molten salt corrosion monitoring. By using the developed sensor, the impurity-driven corrosion of T91 by a fission product, europium, in the LiCl-KCl eutectic molten salt has been studied. The developed minisensor was validated to be an ideal probe for in situ corrosion monitoring in the high-temperature molten salt via the comparisons on concentrations of the dissolved corrosion products detected using this device and inductively coupled plasma mass spectroscopy. To analyze the large volume of data measured using the minisensor during in situ corrosion experiments, an algorithm has been developed to achieve the high-throughput data analysis. The well-designed minisensor can be potentially used for high-throughput corrosion experiments. Combined with the developed algorithm for high-throughput analysis, this study provided a platform to explore the application of electrochemical sensors for the in situ corrosion monitoring of materials in high-throughput molten-salt corrosion experiments.

Datasets for elemental composition of 2LiF-BeF2 (FLiBe) salt purified by hydro-fluorination, analyzed by inductively coupled plasma mass spectrometry (ICP-MS) using two digestion methods.

This article shows the elemental analysis of a batch of FLiBe prepared from LiF and BeF2 and purified by hydro-fluorination, see "Batch-Scale Hydrofluorination of Li2BeF4 to Support Molten Salt Reactor Development" (Kelleher et al., 2015), which was performed by the method of inductively-coupled plasma mass spectrometry (ICP-MS), with analysis samples prepared by multi-acid microwave digestion with and without HF acid. Data shows quantification of a total of sixty-five elements and is reported for a total of eight digested samples. Quantification of 6Li/7Li isotopic ratio is reported for a total of eight digested samples.