A simple method was proposed to produce tungsten (W) particles with controllable shape and size by employing the salt-assisted hydrogen reduction. W particles with controlled shape and size were prepared by adjusting the amount of chlorine salts and the temperature. After adding salt additives, the dispersibility of final particles was obviously improved and more adequate growth of particles was obtained. It was found that the effect of NaCl and LiCl is particularly significant. The average sizes of the obtained W particles at 1038 K after adding 0.1 wt.% NaCl and 0.1 wt.% LiCl were 0.924 and 1.128 μm, respectively. With the increase of temperature and amount of chlorine salts, the dispersity of the produced W particles became much better, the size of W sub-particles was increased, and the shape of W sub-particles was changed from spherical to polyhedral. At 1349 K, the addition of chlorine salts even multiplied the particle size, and the average sizes of W particles with 1 wt.% NaCl and 1 wt.% LiCl were raised up to 21.367 and 29.665 μm, respectively. Based on the conventional pseudomorphic transformation and chemical vapor transport mechanisms, the effects of adding salts on the reaction mechanism were investigated in detail as well.
Abbas Daham,Abdeldjalil Zegaoui,Mehdi Derradji,Athar Ali Khan Gorar,Jun Wang,Bo Tian,Zhong-Cheng Pan,Wen-Bin Liu,Zaoui Moussa
This present investigation reports, for the first time, the properties of the polybenzoxazine bio-based furfurylamine reinforced using the hybrid short carbon fibers and tungsten particles. The results revealed good compatibility between the matrix and the filers using scanning electron microscopy, due to the use of the silane treatment that led to enhanced interfacial bonding. In addition, the mechanical data disclosed that the bending and impact values were respectively increased to 210 MPa and 9 KJ/m2 for the composites containing 20%wt of the short carbon fibers and 20%wt tungsten particles. The hybrid composite shielding properties were evaluated using the cobalt-60 as an irradiation source, and the nuclear results depicted that the half-value length and the tenth-value length were increased as compared to those of the pure polymers. Based on the thermal stability studies, the reinforced hybrid composites also showed excellent thermal resistance.
Microcellular composites combine the advantages of composite material and microcellular material. Introducing the inclusion phase into the polymer matrix can optimize the cellular structure and improve the mechanical properties of microcellular materials. This paper focuses on rigid W particles reinforced PMMA microcellular materials, combining compression experiments and meso FE simulations to investigate the structure–property relationship of cellular structure and compressive properties for W/PMMA microcellular composites. The results indicate that W particles promote heterogeneous nucleation, reducing the cell size to 3 μm, and reinforce the PMMA matrix. W particles (10 → 60 wt%) are linearly and exponentially related to compressive modulus and compressive strength of W/PMMA microcellular composites, increased by 49.3% and 19.8%. Void porosity (71% → 48%) is quadratic related to compressive properties of W/PMMA microcellular composites, increased by 109%. Cell sizes (5 → 1 μm, especially smaller than the W particle sizes) are exponentially related to compressive properties of W/PMMA microcellular composites, increased by 38.5%. This work provides theoretical support for the regulation of cellular structure and optimization of mechanical properties of microcellular materials. Graphical
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