Hot-corrosion of refractory high-entropy ceramic matrix composites synthesized by alloy melt-infiltration. Issue 22 (15th November 2021)

• Record Type: Journal Article
• Authors: Arai, Y.; Saito, M.; Samizo, A.; Inoue, R.; Nishio, K.; Kogo, Y.
• Is Part Of: Ceramics international. Volume 47:Issue 22(2021)
• Page Start: 31740
• Page End: 31748
• Publication Date: 2021-11-15
• Subjects: High-entropy ceramics -- Ceramic matrix composites -- Arc-jet test -- Melt-infiltration -- Hot corrosion; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.08.055
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Carbon fiber-containing refractory high-entropy ceramic matrix composites (C/RHECs) were fabricated through a reaction with carbon powders, transition metal carbides, and Zr–Ti alloys as a novel heat resistant material used for components of hypersonic vehicles cruising at Mach 7–10. With the infiltration of alloys at 1750 °C into a composite preform containing carbon and carbide powders for 15 min, a high-entropy matrix was successfully formed in situ. Arc-jet tests were conducted in the temperature range of 1800–1900 °C. Results showed the formation of an oxidized region composed of complex oxides, such as (Zr, Hf)O2, (Nb, Ta)2 (Zr, Hf)6 O17, (Zr, Hf)TiO4, and Ti(Nb, Ta)2 O7, with an average thickness of ~600 μm, under which an unoxidized region remained. The porous oxidized region resulted from the evolution of CO(g) during oxidation, while a dense oxide region formed as the outermost region. This indicates that the dense oxide region acted as a barrier to oxygen diffusion for the unoxidized region during oxidation.