The role of multi-elements and interlayer on the oxidation behaviour of (Hf-Ta-Zr-Nb)C high entropy ceramics. (November 2020)

• Record Type: Journal Article
• Authors: Wang, Yichen; Zhang, Rui-zhi; Zhang, Buhao; Skurikhina, Olha; Balaz, Peter; Araullo-Peters, Vicente; Reece, Michael J.
• Is Part Of: Corrosion science. Volume 176(2020)
• Publication Date: 2020-11
• Subjects: High entropy carbides -- Transition metal carbides -- Oxidation behaviour -- Interfaces; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2020.109019
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Isothermal oxidation of high entropy carbides was studied at 800−1100 °C in air. Multi-element oxides form in the polycrystalline oxide layer. Oxide layer shows a through thickness distribution of the metals. Amorphous and compact oxycarbide interlayer acts as an oxygen diffusion barrier. Abstract: Isothermal oxidation of (Hf-Ta-Zr-Nb)C high entropy carbide (HEC4) was performed using thermo-gravimetric analysis at 800−1100 °C in air. Polycrystalline oxide layers with multi-element oxides were observed, and their thickness increased with increasing oxidation temperature. Particular attention was paid to the microstructure and role of the interface. An amorphous and compact oxycarbide interlayer was observed between the oxide layer and the bulk carbide in oxidized HEC4, providing an effective diffusion barrier during oxidation. There was a through thickness distribution of the metals in the oxide layer, because of the different oxidation rates and outward diffusion of the cations.