Electronic and elastic properties of perovskite‐like W₃NiC, W₃NiN and Co₃WC from first‐principles calculations

Abstract

We have performed ab initio total energy calculations using the full‐potential linearized augmented plane wave (FP‐LAPW) method with the generalized gradient approximation (GGA) for the exchange–correlation potential to investigate structural, elastic, cohesive, electronic and magnetic properties of the tungsten‐containing perovskite‐like phases W3NiC, W3NiN and Co3WC. The optimized lattice parameters, independent elastic constants (Cij), bulk moduli (B) and shear moduli (G), as well as densities of electronic states and cohesive and formation energies are obtained and analyzed for the first time. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

(W1‐x,Mx)C carbides with desired combinations of compatible density and properties – A first‐principles study

“…Figure 2 shows typical Young's moduli and densities of Sc-, Cr-and Mo-substituted carbides versus the metal concentrations. Compared with WC which has its ρ and E values equal to 15.49 g/cm 3 and 699 GPa, respectively, the Cr-and Mo-substituted carbides have considerably lowered ρ values, while their E values do not decrease much. Carbides substituted by other metals show relatively lower E values but their densities can be even lower such as Ti-substituted carbide.…”

“…55 Figure 3 illustrates E/ρ ratios of WC and metal-substituted carbides. As shown, WC has its ratio of E/ρ equal to 45 GPa/(g/cm 3 ), which is increased by substituting with Cr, Mn, and Mo. In particular, the E/ρ ratio of Cr-substituted carbide (W 1 Cr 3 C 4 ) reaches 68 GPa/(g/cm 3 ).…”

“…This situation was changed with the invention of cemented carbides, where hard WC particles are embedded in a softer matrix (such as Co or Ni). 2,3 The first WC-Co grades were soon applied in the cutting and milling of cast irons with success. The combination of WC and metallic Co as a binder is a well-modified system, possessing combined high hardness and desired fracture toughness.…”

Theoretical studies of the osmium based perovskites AOsO3 (A=Ca, Sr and Ba)

“…Greater the magnitude of cohesive energy of a compound stronger will be its stability and vice versa [34]. In other words this energy is directly related to the strengths of bonds in a compound [35].…”

First-principle studies of the ternary palladates CaPd3O4 and SrPd3O4

“…To discuss the stability of CaPd 3 O 4 and SrPd 3 O 4 compounds, the cohesive energies of these compounds are calculated by the well-known expression [27]…”