Rare-earth-niobate high-entropy ceramic foams with enhanced thermal insulation performance. (20th July 2022)

• Record Type: Journal Article
• Authors: Yang, R.W.; Liang, Y.P.; Xu, J.; Meng, X.Y.; Zhu, J.T.; Cao, S.Y.; Wei, M.Y.; Zhang, R.X.; Yang, J.L.; Gao, F.
• Is Part Of: Journal of materials science & technology. Volume 116(2022)
• Page Start: 94
• Page End: 102
• Publication Date: 2022-07-20
• Subjects: Rare-earth niobate -- High-entropy ceramic foams -- Particle-stabilized foaming -- Atomic-scale analysis -- Thermal conductivity; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2021.10.050
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: Rare-earth-niobate high-entropy ceramics foams were prepared by particle-stabilized foaming. Atomic-scale analysis reveals that high entropy causes atom displacement and lattice distortion. The ceramic foams exhibit high porosity and extremely low thermal conductivity. EMT and GM models are used to analyze the hierarchical pore structures. Abstract: The introduction of porous structures into high-entropy ceramics is expected to further improve its thermal insulation performance. In this work, a series of novel rare-earth-niobate high-entropy ceramic foams ((Dy0.2 Ho0.2 Y0.2 Er0.2 Yb0.2 )3 NbO7 ) with hierarchical pore structures were prepared by a particle-stabilized foaming method. Atomic-scale analysis reveals that high entropy causes atom displacement and lattice distortion. The high-entropy ceramic foams exhibit high porosity (90.13%-96.13%) and ultralow thermal conductivity (0.0343–0.0592 W/(m·K)) at room temperature. High-entropy ceramic foam prepared by a 20 wt% slurry sintered at 1500 °C has the porosity of 96.12% and extremely low thermal conductivity of 0.0343 W/(m·K). The existence of walls and secondary pores contributes to reduced thermal conductivity. There is a temperature difference of over 800 °C between frontside and backside of the sample under fire resistance test. The research indicates that these as-prepared high-entropy ceramic foams are expected to be promising thermal insulation materials. Graphical abstract: Image, graphical abstract