Structural Prediction and Overall Performances of CrSi₂ Disilicides: DFT Investigations

Abstract

Chromium-based silicides (Cr−Si) are broadly used in thermoelectric devices, semiconductors, ultrahigh-temperature devices, and energy-storage systems. However, the structural feature and related properties of CrSi 2 are not clear. Here, the structural, mechanical, and physical performances of CrSi 2 were studied from density functional theory investigations. Four phases: C40 (hexagonal)-CrSi 2 , C11 b (tetragonal)-CrSi 2 , C49 (orthorhombic)-CrSi 2 , and C54 (orthorhombic)-CrSi 2 are considered. In this work, two novel structures: C49 (orthorhombic)-CrSi 2 and C54 (orthorhombic)-CrSi 2 are first predicted. Especially, CrSi 2 with C11 b (tetragonal) has better stability compared to other CrSi 2 . Here, CrSi 2 with the C11 b (tetragonal) phase shows the strongest elastic modulus among all CrSi 2 . However, the Vickers hardness of CrSi 2 with the C49 (orthorhombic) phase is 34.9 GPa. Furthermore, the band gap of CrSi 2 with the C40 (hexagonal) phase and the C54 (orthorhombic) phase is 0.392 and 0.040 eV, respectively, indicating that they are semiconductor materials. Finally, the ultrahightemperature thermodynamic properties of CrSi 2 disilicides are determined from the lattice vibrations of Si and Si−Cr bonds.

Influence of Group III and IV Elements on the Hydrogen Evolution Reaction of MoS2 Disulfide

“…59 A plane-wave basis set with a kinetic energy cutoff of 400 eV was used to describe the balance electrons in all systems. 60,61 The interaction between valence electrons and ionic is treated by the ultrasoft pseudopoten- The tial. 62,63 In the self-consistent field potential and total energy calculations, the Brillouin zone is sampled using the Monkhorst-Pack scheme with a k-point mesh of 9 × 9 × 4.…”

“…All the above calculations are implemented by the CASTEP code. , The local density approximation (LDA) within the CA-PZ scheme is used to describe the electronic exchange correlation interaction . A plane-wave basis set with a kinetic energy cutoff of 400 eV was used to describe the balance electrons in all systems. , The interaction between valence electrons and ionic is treated by the ultrasoft pseudopotential. , In the self-consistent field potential and total energy calculations, the Brillouin zone is sampled using the Monkhorst-Pack scheme with a k-point mesh of 9 × 9 × 4 . The Broyden–Fletcher–Goldfarb–Shannon (BFGS) method is used to optimize the atomic positions and lattice parameters to obtain a fully relaxed structure, − where the total energy, atomic forces, and atomic displacement were less than 2 × 10 –5 eV/atom, 0.05 eV/Å, and 0.002 Å, respectively.…”

Microstructure and Oxidation Behavior of Nb-Si-Based Alloys for Ultrahigh Temperature Applications: A Comprehensive Review

“…It is widely used in Fe-based and Ni-based alloys. The Cr2Nb phase formed after the addition of Cr element in niobium alloy has the advantages of high melting point and oxidation resistance [43][44][45]. The oxide CrNbO4 has better oxidation resistance than Nb2O5, and it can also improve the adhesion between the oxide layer and substrate [46,47].…”

First‐principles investigation of solution mechanism of C in TM‐Si‐C matrix as the potential high‐temperature ceramics

“…[10][11][12][13] Among these high-tempera materials, transition metal silicides have attracted much attention as candidate materials to replace Ni-based superalloys. [14][15][16][17] According to the Si concentrations, transition metal silicides can be divided into TM 5 Si 3 , TMSi 2 , and TM 3 Si. [18][19][20][21] Among them, TM 5 Si 3 silicide has been widely studied due to the high melting point, excellent elastic properties, and high temperature creep resistance.…”