Accelerated Discovery of Corrosion Resistant Materials for Molten Salt Applications
Résumé
In the frame of the French initiative DIADEM (DIscovery Acceleration for the deployment of Emerging Materials), the targeted A-DREAM project aims to develop a generic approach to accelerate the discovery of materials and coatings resistant to corrosion in severe environments. For this, the A-DREAM project proposes an integrated approach implementing: (i) the digital design of materials/coatings, (ii) the high throughput synthesis of these materials and (iii) the implementation of an accelerated corrosion testing methodology.
Firstly, a database is built upon an extensive literature survey where commercial and homemade alloys were tested in molten salts. Secondly, their overall performance is ranked with a pairwise comparison algorithm. Then, the assigned score is fitted as a function of chemical composition by a Gaussian process regression. Lastly, a multi-objective optimization algorithm is applied to obtain the best compromise between corrosion resistance, configurational entropy and microstructural constitution (evaluated by computational thermodynamics).
In the same time, materials are elaborated using a combinatorial PVD process allowing the rapid synthesis of numerous chemical compositions deposited as thin layers on glass substrates. Developments of thicker coatings are also carried out using Cold Spray technology. The corrosion behaviour of these coatings, as well as that of massive materials, is then evaluated using an experimental device allowing the simultaneous testing of a large number of samples from a wide range of materials (metallic and ceramics) and of manufacturing processes for a short duration in molten chlorides at 450 °C. After testing, the corrosion resistance is assessed by mass change, corrosion products dissolved in the salt are analysed by ICP and the corroded sample by GDOES. In the same time, development of an in situ fast-screening electrochemical method is being performed in molten salts together with in situ Raman spectroscopy. The objective is to develop a specific electrochemical cell which will allow the coupling of electrochemical techniques and chemical analyses in order to obtain live corrosion data. Finally, the instrumented electrochemical cell will be implemented in the accelerated corrosion device, with the aim of obtaining an experiment integrating electrochemical analysis, chemical analysis and mass change for high-throughput corrosion testing of materials.
This work has benefited from a government grant managed by the Agence Nationale de la Recherche under the France 2030 program; reference ANR-22-PEXD-0003.