Development of Self-Passivating, High Strength Ferritic Alloys for CSP and TES Application




Concentrating Solar Power, Salt Corrosion Resistance, Protective Al2O3 Scale, Strengthening Laves Phase Precipitation


The addition of aluminum to ferritic stainless steels can result in self-passivation by the formation of a compact Al2O3 top layer, which exhibits significantly higher corrosion resistance to solar salt compared to a Cr2O3 surface layer. The development and qualification of realistic experimental methods for fatigue testing under superimposed salt corrosion attack will enable safe component design. Salt corrosion experiments were carried out at 600 °C with and without mechanical fatigue loading at a novel, self-passivating trial steel, using “solar salt” (60 wt.% NaNO3 and 40 wt.% KNO3). Cyclic salt corrosion tests at 600 °C under flowing synthetic air (without mechanical loading) showed that self-passivation to molten salt attack and mechanical strengthening by precipitation of fine Laves phase particles is possible in novel ferritic HiperFerSCR (Salt Corrosion Resistant) steel. A compact, continuous Al2O3 layer was formed on the surface of the model alloys with Al contents of 5 wt.% and higher. A distribution of fine, strengthening Laves phase precipitates was achieved in the metal matrix.


Download data is not yet available.


R. Guédez, M. Topel, J. Spelling, B. Laumert, "Enhancing the Profitability of Solar Tower Power Plants through Thermoeconomic Analysis Based on Multi-objective Optimization,” Energy Procedia, 69, pp. 1277 – 1286, 2015, DOI:

F. Zaversky, J. García-Barberena, M. Sánchez, D. Astrain, “Transient molten salt two-tank thermal storage modeling for CSP performance simulations,” Solar Energy, 93, pp. 294-311, 2013, DOI:

A. Bonk, C. Martin, M. Braun, T. Bauer, “Material investigations on the thermal stability of solar salt and potential filler materials for molten salt storage,” AIP Conference Proceedings, 1850, 080008, pp. 1-8, 2019, DOI:

A.M. Kuizenga, J.G. Cordaro, “Preliminary Development of Thermal Stability Criterion for Alkali Nitrates,” Sandia Technical Report SAND2011-5837C; Sandia National Laboratories: Albuquerque, NM, USA, 2011.

F. Aarab, B. Kuhn, A. Bonk, T. Bauer, “A New Approach to Low-cost, Solar Salt Resistant Structural Materials for Concentrating Solar Power (CSP) and Thermal Energy Storage (TES),” Metals 2021, 11, 1970, 2021, DOI:

IRENA, “Latest Cost Trends,” in Renewable Power Generation Costs in 2020,”, International Renewable Energy Agency, Abu Dhabi, 2021.

B. Kuhn, T. Fischer, X. Fan, M. Talik, F. Aarab, Y. Yamamoto, „HiperFer - Weiterentwicklungs- und Anwendungspotenzial,“ FVWHT, 43, 2020.

B. Kuhn, M. Talik, T. Fischer, X. Fan, Y. Yamamoto, J. Lopez Barrilao, “Science and Technology of High Performance Ferritic (HiperFer) Stainless Steels,” Metals 2020, 10(4), 463, 2020, DOI:

F. Stein, A. Leineweber, “Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties,” Journal of Materials Science, 56, pp. 5321–5427, 2021, DOI:

J. Hald, “Microstructure and long-term creep properties of 9–12% Cr steels,” International Journal of Pressure Vessels and Piping, 85, pp. 30-37, 2008, DOI:

S. Kobayashi, K. Kimura, K. Tsuzaki, “Interphase precipitation of Fe2Hf Laves phase in a Fe–9Cr/Fe–9Cr–Hf diffusion couple,” Intermetallics, 46, pp. 80-84, 2014, DOI:

S. Kobayashi, “Formation of the Fe2Hf Laves Phase through Eutectoid Type Reaction of δ→γ+Fe2Hf in Ferritic Heat Resistant Steels,” ISIJ International, Vol. 55 (2015), No. 1, pp. 2, 2014, DOI:

F. Aarab, B. Kuhn, “Development of Self-Passivating, High-Strength Ferritic Alloys for Concentrating Solar Power (CSP) and Thermal Energy Storage (TES) Applications,” Energies, 16 (10):4084, 2023, DOI:

B. Kuhn, M. Talik, L. Niewolak, J. Zureka, H. Hattendorf, P.J.Ennis, W.J. Quadakkers, T. Beck, L. Singheiser, “Development of high chromium ferritic steels strengthened by intermetallic phases,” Materials Science and Engineering A, 594, pp. 372–380, 2014, DOI:

X. Fan, B. Kuhn, J. Pöpperlová, W. Bleck, U. Krupp, “Compositional Optimization of High-Performance Ferritic (HiperFer) Steels—Effect of Niobium and Tungsten Content, “ Metals 2020, 10, 1300, 2020, DOI:

M. Żuk, A. Czupryński, D. Czarnecki, T. Poloczek, “The effect of niobium and titanium in base metal and filler metal on intergranular corrosion of stainless steels,” Weld. Tech. Rev., 91, 6, pp. 30-38, 2019, DOI:

T. Beck, B. Kuhn, T. Eckardt, L. Singheiser, “Microstructure, Creep and Thermomechanical Fatigue of Novel Solid Solution and Laves Phase Strengthened Cr2O3 and Al2O3 Forming Ferrites for Car Engine Exhaust and Heat Exchanger Systems,” Trans Indian Inst Met, 69, pp. 379–385, 2016, DOI:

J.K. Lopez Barrilao, B. Kuhn, E. Wessel, “Microstructure and intermetallic particle evolution in fully ferritic steels,“ Proceedings of the 8th International Conference on Advances in Materials Technology for Fossil Power Plants, Albufeira, Portugal; Oct 11th - 14th: pp. 1029–1037, 2016.

J. K. Lopez Barrilao, “Microstructure Evolution of Laves Phase Strengthened Ferritic Steels for High Temperature Applications,” Energie & Umwelt, 375, 2017.

J. Klöwer, “Factors affecting the oxidation behaviour of thin Fe-Cr-Al foils Part II: The effect of alloying elements: Overdoping,” Materials and Corrosion, 51, 5, pp. 373–385, 2000, DOI:<373::AID-MACO373>3.0.CO;2-O

C. Kim, C. Tang, M. Grosse, M. Steinbrueck, C. Jang, Y. Maeng, “Oxidation Kinetics of Nuclear Grade FeCrAl Alloys in Steam in the Temperature Range 600-1500 °C,” Proceedings of TOPFUEL 2021 Conference, Santander, Spain, Oct 24th – 28th, 2021, DOI:

K. O. Gunduz, A. Visibile, M. Sattari, I. Fedorova, S. Saleem, K. Stiller, M. Halvarsson, J. Froitzheim, “The effect of additive manufacturing on the initial High temperature oxidation properties of RE-containing FeCrAl alloys,” Corrosion Science, 188, 109553, 2021, DOI:

Deutsches Institut für Normung e.V., DIN 50905-1, Korrosion der Metalle - Korrosionsuntersuchungen: Teil 1: Grundsätze: Beuth Verlag GmbH; 2009, (DIN 50905-1).

G. Chen, H. Wang, H. Sun, Y. Zhang, P. Cao, J. Wang, “Effects of Nb-doping on the mechanical properties and high-temperature steam oxidation of annealing FeCrAl fuel cladding alloys,” Materials Science and Engineering: A, 803, 140500, 2021, DOI:




How to Cite

Aarab, F., & Kuhn, B. (2024). Development of Self-Passivating, High Strength Ferritic Alloys for CSP and TES Application. SolarPACES Conference Proceedings, 1.

Conference Proceedings Volume


Advanced Materials, Manufacturing, and Components

Funding data