Hierarchical thermal transport mechanisms in Yb2Si2O7 multifunctional thermal and environmental barrier coating (TEBC) material. (15th March 2021)

• Record Type: Journal Article
• Authors: Luo, Yixiu; Yang, Xiaolong; Wang, Jingyang
• Is Part Of: Scripta materialia. Number 194(2021)
• Publication Date: 2021-03-15
• Subjects: Ceramic -- Thermal conductivity -- Modeling -- Phonon engineering; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2020.113704
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: Understanding the mechanism of thermal conduction and its modulation strategy is a threshold task in the search of advanced multifunctional thermal and environmental barrier coating materials (TEBCs). We herein disclose the hierarchical features in the thermal transport of a typical TEBC material, Yb2 Si2 O7, using the state-of-the-art dual-phonon theory. Large amounts of vibrational modes transport heat in a diffusive feature, different from the propagative feature for normal phonons, and make significant contribution to the lattice thermal conductivity ( κ L ) at high temperatures ( T ). This mechanism drives a weak κ L ~ T dependence at high temperatures, deviating from the κ L ~ T −1 trend predicted by the phonon Boltzmann transport equation (BTE) theory. The present study indicates that modulating the κ L of complex-structure low- κ L TEBC materials requires wisdoms beyond the BTE theory and considering the joint effects from different thermal transport channels. Graphical abstract: Image, graphical abstract