Pressureless Sintering of Boron Carbide-Based Superhard Materials

2010 ◽  
Vol 159 ◽  
pp. 145-148 ◽  
Author(s):  
Dimitar D. Radev
Keyword(s):  
Transition Metal ◽  
Boron Carbide ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Vacuum Furnace ◽  
Pressureless Sintering ◽  
Metal Carbides ◽  
Sintering Aids ◽  
Transition Metal Carbides

Boron carbide-based materials B4C-MexBy were densified by pressureless sintering in a vacuum furnace. Some transition metal carbides (TiC, ZrC, HfC, Cr3C2 and WC) from groups IV-VI were used as sintering aids. The optimal sintering temperature in the range 2220-2250oC was used for any composition. Here we show the possibilities to activate the mass transport of the B4C by the mechanism of liquid phase sintering. The method of reactive sintering of B4C in the presence of additives of some transition metal carbides allows in situ synthesis of dense B4C-MexBy materials. Structural properties and fracture toughness of the B4C-based composite materials were discussed. The properties of some of these materials and the possibilities for their application are also discussed.

Atom-precise incorporation of platinum into ultrafine transition metal carbides for efficient synergetic electrochemical hydrogen evolution

2020 ◽  
Vol 8 (9) ◽  
pp. 4911-4919 ◽  
Author(s):  
Xingxing Pan ◽  
Shuanglong Lu ◽  
Duo Zhang ◽  
Ye Zhang ◽  
Fang Duan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Carbon Nanofibers ◽  
Acidic Medium ◽  
Molecular Level ◽  
Engineering Method ◽  
Metal Carbides ◽  
Hybrid Catalyst ◽  
Transition Metal Carbides

A molecular level engineering method is proposed to fabricate ultrafine α-MoC1−x nanoparticles in situ formed on carbon nanofibers with atomic Pt doping. The hybrid catalyst exhibits superior HER electrocatalytic performance in acidic medium.

scholarly journals In situ atomistic insight into the growth mechanisms of single layer 2D transition metal carbides

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiahan Sang ◽  
Yu Xie ◽  
Dundar E. Yilmaz ◽  
Roghayyeh Lotfi ◽  
Mohamed Alhabeb ◽  
...  
Keyword(s):  
Transition Metal ◽  
Single Layer ◽  
Metal Carbides ◽  
Growth Mechanisms ◽  
Transition Metal Carbides ◽  
Insight Into

scholarly journals Carbothermal and boron carbide reduction of oxides of some transition metals

2021 ◽  
Vol 340 ◽  
pp. 01040
Author(s):  
Yuriy L. Krutskii ◽  
Tatiana M. Krutskaya ◽  
Tatiana S. Gudyma ◽  
Konstantin B. Gerasimov ◽  
Roman R. Khabirov ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Boron Carbide ◽  
High Performance ◽  
Chemical Interaction ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Optimum Synthesis ◽  
Viable Method ◽  
Reduction Of Oxides

The study presents a possible mechanism to produce carbides and diborides of transition metals, such as titanium, vanadium, chromium and zirconium. The carbothermal synthesis of transition metal carbides has defined the direct dependence between the thermodynamic stability of oxides and the temperature range of the reduction onset (the stronger the oxide, the higher the value of the temperature is). It reaches 2000-2100, 1500-1600, 1300-1400 and 2100-2200°C for such carbides as TiC, VC0,88, Cr3C2 and ZrC respectively. The same dependence has not been found for the diborides of these metals. Optimum synthesis temperatures for all these compounds lie in the range of 1600-1700 °C. This viable method to produce transition metal carbides consists in the transfer of vaporous higher and lower oxides. Diborides preparation involves the transfer of oxides and boron vapors onto the surface of the carbon material with the subsequent chemical interaction. In the case of carbide-boron reduction of zirconium oxide in excess of boron carbide, the reaction product will be a composite material (B4C – ZrB2). The ceramics based on this composite possesses high performance properties.

scholarly journals Atomic-resolution in-situ cooling study of functionally terminated 2D transition metal carbides.

2021 ◽  
Vol 27 (S1) ◽  
pp. 658-660
Author(s):  
Francisco Lagunas ◽  
Chenkun Zhou ◽  
Dmitri Talapin ◽  
Robert Klie
Keyword(s):  
Transition Metal ◽  
Atomic Resolution ◽  
Metal Carbides ◽  
Transition Metal Carbides

Pressureless Sintering and Properties of Boron Carbide-Titanium Diboride Composites by In Situ Reaction

2012 ◽  
Vol 525-526 ◽  
pp. 321-324 ◽  
Author(s):  
Ai Dong Liu ◽  
Ying Jie Qiao ◽  
Ying Ying Liu
Keyword(s):  
Flexural Strength ◽  
Boron Carbide ◽  
Titanium Diboride ◽  
Sintering Temperature ◽  
High Density ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
In Situ Reaction

Pressureless sintering to obtain high density boron carbide-titanium diboride composites by in-situ reaction was studied. Pressureless sintering behavior of this material was investigated between 1800-2150 .The effects of composition, sintering temperature and tine were examined. Density up to 98.5% T.D. was reached at 2150. Maximum values of flexural strength (502 MPa), hardness (33 Gpa) and fracture toughnes (4.6 MPa·m1/2) were observed in the specimens containing 15 vol.% TiB2.

Tuning Transition Metal Carbides Activity by Surface Metal Alloying: Case Study on CO2 Capture and Activation

2018 ◽  
Author(s):  
Marti Lopez ◽  
Luke Broderick ◽  
John J Carey ◽  
Francesc Vines ◽  
Michael Nolan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Co2 Capture ◽  
Density Functional ◽  
Deep Understanding ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Adsorption Sites ◽  
Surface Metal ◽  
A Minor

<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>

scholarly journals Predicting the Effect of Dopants on CO2 Adsorption in Transition Metal Carbides: Case Study on TiC (001)

2020 ◽  
Vol 124 (29) ◽  
pp. 15969-15976 ◽  
Author(s):  
Martí López ◽  
Francesc Viñes ◽  
Michael Nolan ◽  
Francesc Illas
Keyword(s):  
Transition Metal ◽  
Co2 Adsorption ◽  
Metal Carbides ◽  
Transition Metal Carbides

Explaining stability of transition metal carbides – and why TcC does not exist

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

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

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