scholarly journals Review of phase stability in the group IVB and VB transition‐metal carbides

2018 ◽  
Vol 101 (10) ◽  
pp. 4401-4424 ◽  
Author(s):  
Christopher R. Weinberger ◽  
Gregory B. Thompson
Author(s):  
Christopher R. Weinberger ◽  
Gregory B. Thompson

The crystal structure and composition of the zeta phase in the group VB transition metal carbides are not completely understood despite decades of experimental studies. As such, the phase rarely appears on phase diagrams of the group VB transition metal carbides. There is currently renewed interest in this phase, as tantalum carbide composites exhibit high fracture toughness in the presence of this phase. This work extends the initial computational study using density functional theory of the phase stability of the zeta phase in the tantalum carbide system, where the tantalum carbide zeta-phase crystal structure and stability were determined, to the niobium and vanadium carbides. It is shown that the zeta phases in the three systems share the same crystal structure and it is an equilibrium phase at low temperatures. The carbon atom ordering in the three different phases is explored and it is demonstrated that the zeta phase in the tantalum carbides prefers to order carbon atoms differently than in the niobium and vanadium carbide zeta phases. Finally, the properties of this crystal are computed, including elastic constants, electronic densities of states and phonon dispersion curves, to illustrate that this crystal structure is similar to other transition metal carbides.


2019 ◽  
Vol 166 ◽  
pp. 271-280 ◽  
Author(s):  
Tyler J. Harrington ◽  
Joshua Gild ◽  
Pranab Sarker ◽  
Cormac Toher ◽  
Christina M. Rost ◽  
...  

2001 ◽  
Vol 333 (6) ◽  
pp. 444-450 ◽  
Author(s):  
H.W. Hugosson ◽  
U. Jansson ◽  
B. Johansson ◽  
O. Eriksson

2018 ◽  
Author(s):  
Marti Lopez ◽  
Luke Broderick ◽  
John J Carey ◽  
Francesc Vines ◽  
Michael Nolan ◽  
...  

<div>CO2 is one of the main actors in the greenhouse effect and its removal from the atmosphere is becoming an urgent need. Thus, CO2 capture and storage (CCS) and CO2 capture and usage (CCU) technologies are intensively investigated as technologies to decrease the concentration</div><div>of atmospheric CO2. Both CCS and CCU require appropriate materials to adsorb/release and adsorb/activate CO2, respectively. Recently, it has been theoretically and experimentally shown that transition metal carbides (TMC) are able to capture, store, and activate CO2. To further improve the adsorption capacity of these materials, a deep understanding of the atomic level processes involved is essential. In the present work, we theoretically investigate the possible effects of surface metal doping of these TMCs by taking TiC as a textbook case and Cr, Hf, Mo, Nb, Ta, V, W, and Zr as dopants. Using periodic slab models with large</div><div>supercells and state-of-the-art density functional theory based calculations we show that CO2 adsorption is enhanced by doping with metals down a group but worsened along the d series. Adsorption sites, dispersion and coverage appear to play a minor, secondary constant effect. The dopant-induced adsorption enhancement is highly biased by the charge rearrangement at the surface. In all cases, CO2 activation is found but doping can shift the desorption temperature by up to 135 K.</div>


2020 ◽  
Vol 124 (29) ◽  
pp. 15969-15976 ◽  
Author(s):  
Martí López ◽  
Francesc Viñes ◽  
Michael Nolan ◽  
Francesc Illas

RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16197-16202 ◽  
Author(s):  
Qinggao Wang ◽  
Konstantin E. German ◽  
Artem R. Oganov ◽  
Huafeng Dong ◽  
Oleg D. Feya ◽  
...  

A simple understanding on the trend of stability for transition metal carbides.


2011 ◽  
Vol 31 (3) ◽  
pp. 421-427 ◽  
Author(s):  
Ji Zou ◽  
Guo-Jun Zhang ◽  
Shi-Kuan Sun ◽  
Hai-Tao Liu ◽  
Yan-Mei Kan ◽  
...  

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