Spontaneous formation of multilayer refractory carbide coatings in a molten salt media

Loic Constantin (1) , Lisha Fan (1) , Mathilde Pouey (2) , Jérôme Roger (3) , Bai Cui (4) , Jean-François Silvain (2) , Yong Feng Lu (1)

1 Department of Electrical and Computer Engineering
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 LCTS - Laboratoire des Composites Thermostructuraux
4 Department of Mechanical and Materials Engineering

Refractory materials hold great promise to develop functional multilayer coating for extreme environments and temperature applications but require high temperature and complex synthesis to overcome their strong atomic bonding and form a multilayer structure. Here, a spontaneous reaction producing sophisticated multilayer refractory carbide coatings on carbon fiber (CF) is reported. This approach utilizes a relatively low-temperature (950 °C) molten-salt process for forming refractory carbides. The reaction of titanium (Ti), chromium (Cr), and CF yields a complex, high-quality multilayer carbide coating composed of 1) Cr carbide (Cr 3 C 2 ), 2) Ti carbide, and 3) Cr 3 C 2 layers. The layered sequence arises from a difference in metal dissolutions, reactions, and diffusion rates in the salt media. The multilayer-coated CFs act as a permeable oxidation barrier with no crystalline degradation of the CFs after extreme temperature (1,200 °C) and environment (oxyacetylene flame) exposure. The synthesis of high-quality multilayer refractory coating in a fast, efficient, easy, and clean manner may answer the need for industrial applications that develop cheap and reliable extreme environment protection barriers.

Mots clés: Physical sciences; Engineering molten salt synthesis; oxidation barrier; multilayer coating; refractory carbide; carbon fibers

Domaines: Matériaux

Loic Constantin, Lisha Fan, Mathilde Pouey, Jérôme Roger, Bai Cui, et al.. Spontaneous formation of multilayer refractory carbide coatings in a molten salt media. Proceedings of the National Academy of Sciences of the United States of America, 2021, 118 (18), e2100663118 (5 p.). ⟨10.1073/pnas.2100663118⟩. ⟨hal-03211019⟩