tungsten nanoparticles
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Author(s):  
Samy Selim ◽  
Hamada AbdElgawad ◽  
Ahmed Mohamed Reyad ◽  
Bassam F. Alowaiesh ◽  
Nashwa Hagagy ◽  
...  

2021 ◽  
Vol 2094 (4) ◽  
pp. 042088
Author(s):  
A V Ozolin ◽  
E G Sokolov

Abstract The effect of tungsten nanoparticles on the kinetics of sintering of the Sn-Cu-Co-W powder material used as a binder in diamond tools was studied. The W16,5 grade tungsten powder was mechanically activated in the AGO-2U planetary centrifugal mill for 60 minutes at the carrier rotation frequencies of 800 RPM. The mixture of tungsten, tin, copper, and cobalt powders was compacted by static pressing in press dies and then sintered in vacuum at the temperature of 820°C. The morphology and sizes of powder particles, as well as the structure of the sintered samples, were studied by the methods of scanning electronic microscopy. It has been demonstrated that tungsten nanoparticles have a noticeable effect on the process of dissolution-reprecipitation of cobalt in liquid-phase sintering.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 761
Author(s):  
Maria Myachina ◽  
Natalia Gavrilova ◽  
Ksenia Poluboyarinova ◽  
Victor Nazarov

Herein, we demonstrate a promising method for the synthesis of ultrafine carbide particles using dispersions of molybdenum–tungsten nanoparticles. Dispersions of molybdenum–tungsten blue nanoparticles with different initial molar ratios of molybdenum/tungsten were synthesized through the reduction of molybdate and tungstate ions by ascorbic acid in an acidic medium (pH = 1.0–2.5). Molybdenum–tungsten blue nanoparticles were characterized by ultraviolet–visual (UV–VIS), infrared (FTIR), and X-ray photoelectron (XPS) spectroscopies; transmission electronic microscopy (TEM); and dynamic light scattering (DLS). We demonstrated that molybdenum–tungsten blue nanoparticles belong to toroidal polyoxometalate clusters (λmax = 680–750 nm) with a predominant particle size of 4.0 nm. Molybdenum–tungsten blue dispersions were shown to be monodispersed systems with a small particle size and long-term stability (>30 days) and are suitable for further catalytic applications.


2020 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Maria Myachina ◽  
Natalia Gavrilova ◽  
Ksenia Poluboyarinova ◽  
Victor Nazarov

A promising method for the synthesis of ultrafine carbide particles is the sol–gel method using dispersions of molybdenum–tungsten nanoparticles. For further use, the main properties of molybdenum-blue nanoparticles, including the size, structure, and stability, under different conditions must be determined. The synthesis of dispersions of molybdenum–tungsten blue was carried out as a result of the reduction of molybdate and tungstate ions in the presence of hydrochloric acid. Ascorbic acid was chosen as a reducing agent and further acted as a carbon source. Dispersions and nanoparticles were investigated by transmission electronic microscopy (TEM), UV/vis and infrared (FTIR) spectroscopy, and dynamic light scattering (DLS).


2020 ◽  
Vol 59 (21) ◽  
pp. 15690-15695
Author(s):  
Masanori Wakizaka ◽  
Wang-Jae Chun ◽  
Takane Imaoka ◽  
Kimihisa Yamamoto

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