Approximate lattice thermal conductivity of MAX phases at high temperature

Abstract

The temperature dependent lattice thermal conductivity (κ ph ) of MAX phases, M n+1 AX n are calculated using the Debye theory as outlined by Slack. At high temperature the formula derived by Slack is a reasonable approximation to estimate the lattice thermal conductivity. The calculation used the large data base of elastic coefficients of stable MAX phases established recently. It is found that MAX phases with "A" = Al have higher κ ph at 1300 K, and the majority of MAX carbides have higher κ ph than MAX nitrides. We have also calculated the minimum thermal conductivities of these MAX phases using the empirical formula suggested by Clarke. It is shown that the minimal lattice thermal conductivities of MAX carbides and nitrides are closer to each other in the 211 phases than in higher n phases. The calculated κ ph for 8 MAX phases at 1300 K are in reasonable agreement with experimental data, especially in Ti 2 AlC, Nb 4 AlC 3 , Ta 4 AlC 3 , Nb 2 AlC and Nb 2 SnC phases.

Possible new metastable Mo2Ga2C and its phase transition under pressure: a density functional prediction

“…1b, c. In both e-and m-structures, phonon band gaps are observed. The PPDOS of C atoms locate mainly above the gap, and PPDOS of Mo and Ga atoms are in lower energy range, which is consistent with the common features found in phonon spectra of other MAX phases [41][42][43]. However, noticeable difference in PPDOS for Ga atoms of two structures is observed.…”

Wearable Electronics Based on 2D Materials for Human Physiological Information Detection

“…Recently, the ternary carbides and nitrides with a general formula MAX (M n +1 AX n ), where n is 1, 2, or 3, M is an early transition metal, A is mainly a group IIIA or IVA element, and X is C and/or N, have been augmented to the 2D materials family (Figure h). So far, more than 70 known MAX phases sharing layered hexagonal with space group P6 3 /mmc have been reported . As we can see from Figure h, two A element layers in MAX phases sandwiches the early transition metal carbides and/or nitrides layer.…”

“…Copyright 2013, Nature Publishing Group; i) corresponding TEM and high‐resolution TEM images of MoS 2 (right) and WS 2 (left); Reproduced with permission . Copyright 2010, Wiley‐VCH; h) three typical MAX phases with ternary layered transition metal carbides and nitrides; Reproduced with permission . Copyright 2015, Elsevier; j) TEM and high‐resolution TEM images typical Ti 3 C MXene; Reproduced with permission .…”

A Tetrakis(terpyridine) Ligand–Based Cobalt(II) Complex Nanosheet as a Stable Dual‐Ion Battery Cathode Material

“…Since the successful isolation of graphene, [ 1 ] 2D polymers, such as nanosheets have attracted increasing attention thanks to their unique physical, electronic, and chemical properties originated from their nature of electron confinement in two dimensions. To expand this nascent field in terms of ultrathin architectures and then meet the demands in various application fields, a series of graphene‐like 2D materials, including MXenes, [ 2,3 ] metal oxides, [ 4,5 ] and metal hydroxides [ 6,7 ] were investigated. The declaration of bandgap transition in single‐layer molybdenum disulfide [ 8 ] further boosted the development of the transition metal dichalcogenides (TMD).…”