A Theoretical Investigation on the Anisotropic Surface Stability and Oxygen Adsorption Behavior of ZrB₂

Abstract

Surfaces play pivotal roles during the oxidation and interfacial bonding of ZrB2. To understand the surface properties, the anisotropic stability and oxygen adsorption behavior of ZrB2 surfaces, including (11bold2¯0), two types of (0001) and three types of (10bold1¯0), were investigated by first‐principles calculations. Using a series of two‐region models, the surface energies were calculated and the (0001) surfaces were found to be less stable than the prismatic ones. The hexagonal rod‐like ZrB2 grain morphology was predicted during the crystal growth under equilibrium conditions. The adsorption energies, electronic structure, and bonding feature of the adsorbed surfaces were also investigated. The Zr‐terminated surfaces were predicted to be more favorable to adsorb oxygen, and the (0001) surfaces should have better oxidation resistance than other surfaces in the equilibrium ZrB2 grains. The Zr‐terminated (0001) surface was also speculated to be stable in the oxygen‐rich environment.

Atomistic simulations of surface reactions in ultra-high-temperature ceramics: O2, H2O and CO adsorption and dissociation on ZrBZhang1, Sanvito2 2021Applied Surface Science6000View full textAdd to dashboardCite

“…In more detail we find for O the following ∆E ads , 9.06, 3.44, 5.81, 8.59, 6.86, 6.43 and 5.42 (in eV/atom), respectively, at the sites H1, H2, H3, B1, B2, A1 and A2. These values agree well with those from references [10,12]. Furthermore, ∆E ads for H is also in good agreement with that found by Xiao and coworkers [28].…”

“…For example, by using density functional theory (DFT) calculations, Sayós et al [10] proposed that the adsorption of atomic O on the ZrB 2 (0001) surface takes place predominantly at the hollow and B-B bridge sites. Zhou et al [11,12] emphasized the effects of the valance electron concentration on the surface stability and oxygen adsorption. The theoretical study of oxidation of ZrB 2 (0001) surface from Cheng et al [13] suggested that the initial oxygen coverage has only little effect on the oxidation reaction.…”

“…Figure 2: (a) Polar diagram of the adsorption energies, ∆E ads (eV/atom), for the chemical species O, C, OH and H.Here H1, B1 and A1 (green shadow) are adsorption sites on (0001) Zr , and H2, H3, B2 and A2 (grey shadow) are on the (0001) B surface. Our results in black are compared with those from Sayós's[10] in blue, Zhou's[12] in green and Xiao's[28] in red (note the latter two are shifted by half of the binding energies of O2 and H 2 , respectively). (b) The disturbance of the adsorbent surface, ∆max (Å), are measured by the maximum displacement of the first atomic layer on the surface.…”

Chrysanthemum-like high-entropy diboride nanoflowers: A new class of high-entropy nanomaterials

“…For high-entropy metal diborides, the {100} plane possessed the highest surface desorption energy (Edes) among all the crystal facets. 38 Consequently, the growth velocity of the <100> direction should be the highest among all directions in thermodynamics. However, in a realistic crystal growth process, some environmental factors of the system, such as impurity pinning site, adsorbed surfactants, and transport kinetics, are complicated and varied, which can also result in the highest growth velocity in other directions in addition to <100> direction.…”

Modulation Effect of Hardness on the Friction Coefficient and Its Mechanism Analysis of ZrB2/Mo Multilayers Synthesized by Magnetron Sputtering

“…Therefore, it is necessary to establish a method that can effectively improve the mechanical properties, high temperature resistance, and friction properties of the multilayer. Among many materials, ZrB 2 has the advantages of a high melting point, high hardness, low density, excellent corrosion resistance and oxidation resistance [10][11][12][13][14][15][16], and it is a promising ultra-high temperature ceramic material. Over the years, despite extensive research on the microstructure and mechanical properties of ZrB 2 [17,18], its application was still limited by its inherent brittleness, low fracture toughness, and unreliable high temperature performance [19,20].…”