ELECTROCHEMISTRY COMMUNICATIONS
·
2021
·
IF 4.724
Liwen Zhang,Xiaoli Xi,Zuoren Nie
A new electrochemical method for efficient and green recovery of cemented carbide in a molten salt is described. Tungsten powder is the main product when recovering cemented carbide by molten salt electrolysis. However, the main purpose of tungsten powder is to make tungsten carbide. Based on this, a new method for preparing tungsten carbide by in situ reduction was developed. Pure tungsten carbide powder was successfully prepared in situ by pulse electrolysis in a NaF–KF molten salt system at 1073 K. This not only effectively recovers the spent cemented carbide, but also enriches the product system and optimizes the method for preparation of tungsten carbide powder.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Yuhui Chen,Zhenhua Hao,Rulong Ma,Pei Wang,Yongchun Shu,Jilin He
In this study, a new unmixed carbon reduction method was proposed for the preparation of pure W powder. The effects of reduction temperature, reduction time, carbon distance and thickness of WO 3 layer on the phase of the reduction products were investigated. Results show that pure tungsten powder with a carbon content of less than 150 ppm can be prepared at 950 °C with a WO 3 layer thickness of 5 mm and a carbon distance of 2 mm. Increased carbon distance and thickness of WO 3 layer will lead to a decrease in the reduction ratio. Additionally, particle size of the tungsten powder gradually increases from 1 μm to 8 μm due to sintering with the extended reduction time. Furthermore, a two-stage carbon reduction process with WO 2 as an intermediate product is proposed, which avoids the sintering and growth of tungsten powder particles and the particle size of tungsten powder was successfully reduced to 2 μm. This unmixed carbon reduction reduces the carbon concentration and prevents the carbonization of tungsten powder. The experiment verifies the feasibility of carbon as a reducing agent in producing pure tungsten powder by reducing WO 3 .
研究领域:
材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2019
·
IF 3.25
Zepeng Lv,Dong Liu,Yijie Wu,Run Zhang,Haibo Sun,Jie Dang,Liwen Hu
Tungsten, one of the refractory metals, has lots of excellent properties, making tungsten powders become a choice of raw material for many applications. This work reported a simple method (the salt-assisted hydrogen reduction of WO 3 powders) for preparing tungsten powders with desired morphologies and size. By adjusting the amount of additive (Y(NO 3 ) 3 ) and reduction temperature, metallic tungsten particles with different morphologies and size were obtained. It was found that both temperature and additive had apparent effects on the morphology and size of metallic W particles, and the large parallelepiped-shaped powders disappeared and large irregular blocky-shaped powders were degraded under the influence of additive. With the increase of temperature and amount of salt, particles became more dispersed and the size increased at higher temperatures, and the shape of particles was changed from spherical to polyhedral as well. On the contrary, the size of sub-particles became smaller as increasing amount of Y(NO 3 ) 3 at lower temperatures. Based on the results, the reaction and refining mechanisms for preparing tungsten were proposed as well.
研究领域:
材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Qiao Yin,Chen Lai,Shuqun Chen,Jian Peng,Hongyi Li,Wenyuan Zhou,Peng Hu,Jinshu Wang
In this article, Ni-coated W powders were firstly prepared by a liquid-solid doping method combined with air calcination and hydrogen reduction. X-ray diffraction analysis, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and temperature programmed reduction analysis were carried out to investigate the nickel doping process in WO 3 and its influence on the reduction behaviors of tungsten oxides. It reveals that after calcinations most Ni ions would occupy the lattice sites of host W ions and decrease the interplanar spacing of WO 3 . The latter is due to the promotion of oxygen vacancy generation within WO 3 rather than the changes in ionic radius. After hydrogen reduction, the doped Ni atoms precipitate onto the surface of W particles as thin metallic coatings, whereby the size and morphology of reduced W particles are varied greatly with increasing Ni addition. The presence of Ni has also been found to lower the reduction barriers for WO 3 by using first-principles calculation. Finally, W-Ni compacts were sintered at 1500 °C in hydrogen atmosphere and the accelerated densification phenomenon of W alloy upon Ni doping is discussed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2024
·
IF 4.2
Hengli Li,Huijun Shang,Feng Pan,Weijun Li,Zhan Du
This article investigated the preparation of ultrafine W powder by fluidized bed hydrogen reduction, and the apparent activation energy was determined for various reduction stages by using temperature programmed reduction with hydrogen. The results demonstrate that the introduction of Co 3 O 4 significantly enhances the reduction process of WO 3 .High Co 3 O 4 content can lead to the formation of CoWO 4 in the initial stage and obtain products with high content of Co 3 W. An increase in the Co 3 O 4 content correlates with a gradual decrease in the particle size of the product. The apparent activation energy for the WO 3 → WO 2 and WO 2 → W processes decreases as the Co 3 O 4 content increases. It can be decreased from 105.59 kJ /mol to 78.72 kJ/mol for the WO 3 → WO 2 stage, and from 107.38 kJ/mol to 78.38 kJ/mol for the WO 2 → W stage, respectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2024
·
IF 2.7
Yuhui Chen,Zhenhua Hao,Rulong Ma,Pei Wang,Yongchun Shu,Jilin He
Ultrafine tungsten (W) powder was prepared by a non-contact carbon reduction followed by hydrogen reduction method. In this process, WO 3 and activated carbon were separated by a porous plate and the reduction of tungsten oxide was achieved by carbon atoms diffusion at high temperature. This method can stably prepare violet tungsten oxide powder with low carbon content (194 ppm) using activated carbon as a reducing agent. It avoids the problem that the high residual carbon in reduction products in traditional carbon reduction experiment. Then, ultrafine tungsten powder with an average particle size of less than 100 nm was prepared by hydrogen reduction of violet tungsten oxide.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2018
·
IF 3.398
Ming Li,Xiaoli Xi,Zuoren Nie,Liwen Ma,Qingqing Liu
The recycling of WC–Co hard metal scraps has been taken into consideration in the literature, due to the release of toxic substances and long recovery process. In this study, the recovery of tungsten process, based on the molten salt electrolysis treatment of WC–Co hard metal scraps, was developed. The anode polarization curves were applied to investigate the dissolution of the WC–Co hard metal scrap. Then, the electrochemical behavior of tungsten and cobalt ions dissolved from WC–Co scrap anode, was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). The results demonstrated that the reduction of tungsten and cobalt ions occurred through a one-step process involving the transfer of two electrons. This process was achieved by the diffusion of tungsten and cobalt ions in the melts. Finally, the parameters, such as the electrolysis current, the electrolysis duration and temperatures, were applied to analyze the effect of different electrolysis conditions on the composition of recycled products. The results demonstrated that the electrolysis current and the electrolysis temperature, compared to electrolysis duration, have significant effects on the selectivity of tungsten recycling. Furthermore, the analysis of cathode products demonstrated that a tungsten powder of approximately 500 nm could be selectively recovered from WC–Co hard metal scrap with the electrolysis condition of 60 mA for 4 h at 1073 K in NaF–KF molten salt.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2025
·
IF 4.5
Xiyang Liu,Lihua Guo,Jinpeng Zhang,Guoqiang Wang,Linyuan Lu,Jun Lin,Jinwei Zhan
Tungsten (W) stands out as one of the most promising matrix materials for cermet fuels in nuclear thermal propulsion (NTP) systems, with its effective thermal conductivity (ETC) being intricately linked to the economic viability and safety of reactors. This study investigated the influence of sintering temperature on the microstructure of nanoscale W powder using Spark Plasma Sintering (SPS). Based on the microstructural evolution observed at various temperatures, both a finite element (FE) model and an Artificial Neural Network (ANN) model were employed to assess the ETC of the W matrix, and the ETC was experimentally measured using the frequency-domain thermoreflectance (FDTR) method. The FE simulation results reveal a 7.5 % average relative error between modeled and measured ETC values at high sintering temperatures, demonstrating good consistency between simulation and experiment. Further analysis reveals that the porosity of the W matrix significantly affects its ETC. As the sintering temperature increases from 1273 to 1973 K, the porosity decreases from 32.48 % to 3.86 %, while the ETC increases from 46.07 to 160.71 W/(m·K). The ANN results demonstrate that the trained ANN model could accurately assess the ETC of the W matrix, with a regression coefficient of 0.9983 for the trained dataset and 0.9922 for the tested dataset. Based on the relationship between porosity and ETC, an optimized formula has been developed for predicting the ETC of the W matrix with an R² value of 0.9954 and an RRMSE of 2.37 %. The ANN model established in this study provides an accurate method for predicting the ETC of W and offers new insights and references for predicting the ETC of other materials.
研究领域:
材料科学
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核工程
·
机器学习
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热分析
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微观结构建模
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Tiantian Chen,Jie Chen,Zhenyu Yi,Congqin Zheng,Linming Zhou,Yongjun Wu,Feiyan Cai,Jiale Qin,Zijian Hong,Yuhui Huang
Transcranial ultrasound imaging and therapy have gained significant attention due to their noninvasive nature, absence of ionizing radiation, and portability. However, the presence of the skull, which has a high acoustic impedance, presents a challenge for the penetration of ultrasound into intracranial tissue. This leads to a low transmission of ultrasound through the skull, hindering energy focusing and imaging quality. To address this challenge, we propose a novel approach that utilizes a flexible matching layer with gradual acoustic impedance to enhance ultrasound transmission through the skull. This matching layer is constructed using Poly(dimethylsiloxane) (PDMS)/tungsten powders as the structural component responsible for the gradual impedance, while agarose serves as the flexible matrix. Our simulation and experimental results demonstrate that the matching layer with an exponential gradual acoustic impedance significantly improves the ultrasound transmission coefficient across a wide frequency range compared to traditional quarter wavelength matching layers. Specifically, at 2 MHz, the maximum transmission coefficient reaches 49.5%, more than four times higher than that of the skull without a matching layer (only 11.7%). Additionally, the good flexibility of our matching layer ensures excellent adhesion to the curved surface of the skull, further enhancing its application potential in transcranial ultrasound imaging and therapy. The improved transmission performance allows for a lower ultrasound transmission power, effectively addressing overheating and safety issues.
研究领域:
医学成像
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生物医学工程
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超声治疗
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Yu Fang,Zheng Tang Cai,Ze Wei Zhu,Jia Hao Ma,Hong Kai Cai,Han Li
SnTe has attracted significant attention as a promising thermoelectric material due to its favorable band structure and low cost. However, its high intrinsic hole concentration and thermal conductivity still hinder further performance enhancement. In this study, a series of Sn 2.9-x W x Te 2.9 –(In 2 Te 3 ) 0.03 –(Cu 2 Te) 0.18 (x = 0, 0.03, 0.06, 0.09, 0.12, 0.15) composites were synthesized by incorporating in-situ formed In 2 Te 3 and Cu 2 Te nanophases along with W doping. Structural and microstructural analyses confirmed the formation of uniformly distributed nanoinclusions (10–20 nm) and homogeneous elemental distribution. W doping effectively suppressed intrinsic Sn vacancies and induced valence band convergence, while the introduction of In created resonant states. These synergistic effects significantly enhanced the Seebeck coefficient. Moreover, multiscale phonon scattering arising from nanophases, dislocations, and lattice distortions greatly reduced the lattice thermal conductivity. The sample with x = 0.09 exhibited a maximum power factor of 25.98 μW·cm −1 ·K −2 , while the sample with x = 0.12 achieved a minimum lattice thermal conductivity of 0.406 W·m −1 ·K −1 . As a result, the optimized composition reached a peak ZT of 1.23 and an average ZT of 0.44 at 823 K, representing improvements of approximately 209 % and 215 % over pristine SnTe, respectively. These results place the material among the top-performing SnTe-based thermoelectric systems reported to date.
研究领域:
材料科学
·
热电材料
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纳米材料
·
能量转换
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2025
·
IF 26.8
Haoyu Yue,Zhongnan Guo,Wenjing Guo,Ruonan Yao,Shuang Zhen,Qiansu Ma,Ming Chen,Jiawei Lin,Wenxia Yuan
The high-entropy strategy offers a viable pathway to activate the inert basal plane of transition metal dichalcogenides (TMDs) for electrocatalysis. This work demonstrates that the “lattice distortion effect”, one of the core effects of high-entropy materials, plays a crucial role in activating the basal plane of TMDs. A high-entropy diselenide (ReNbTaMoW)Se 2 (denoted as HESe 2 ) is synthesized via solid-state reaction. Single-crystal X-ray diffraction and atomic resolution scanning transmission electron microscopy reveal a unique fivefold-modulated structure in HESe 2 , which unexpectedly distorts the rigid trigonal prismatic motif. HESe 2 exhibits exceptional activity for hydrogen evolution reaction (HER), showing a low overpotential of 31 mV at a current density of 10 mA cm −2 , comparable to state-of-the-art precious metal catalysts. In situ X-ray photoelectron spectroscopy indicates that the distorted structure of HESe 2 remains stable during the HER process. A proton exchange membrane (PEM) electrolyser assembled with HESe 2 cathodic catalyst shows competitive performance and durability with negligible degradation over 400 h. Density functional theory calculations reveal the electron accumulation regions induced by lattice distortion as high-activity sites, thereby driving the augmented HER performance of HESe 2 . This work presents a universal strategy for boosting the basal plane activity of layered materials through unique lattice distortion effect.
研究领域:
材料科学
·
电化学
·
催化
·
能源材料
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 7
·5242-5251
·
IF 4.6
Qiyuan Zhang,Ruoming Du,Aihua Yao
Recent advances in hydrated tungsten oxides (WO3·nH2O, n = 1, 2) have highlighted their potential for dual-band electrochromic applications. However, achieving both high optical modulation and robust cycling stability remains a challenge. This study presents a cost-effective and straightforward cathodic electrodeposition method to fabricate amorphous tungsten oxide dihydrate (WO3·2H2O) films using a precursor solution primarily composed of monomeric diperoxotungstate. The open framework and interlayer structural water in WO3·2H2O enable exceptional dual-band electrochromic performance at super-low switching potentials (−0.5 V for full coloration and 0.5 V for full bleaching) in a 1.0 M LiClO4/propylene carbonate (LiClO4/PC) electrolyte. Key features include high optical modulation (∼92% at 633 nm and ∼86% at 1100 nm), fast response times (17.5 s for bleaching and 18.1 s for coloration at 633 nm; 5.0 s for bleaching and 7.1 s for coloration at 1100 nm), high coloration efficiencies (204.2 cm2 per C at 1100 nm and 72.3 cm2 per C at 633 nm), and exceptional cycling stability (retaining 94% of initial optical modulation after 2000 cycles and 76% after 10 000 cycles at 633 nm). The interlayer water in WO3·2H2O plays a critical role in facilitating pseudocapacitive Li+ intercalation, enabling control over optical properties across the visible and near-infrared (NIR) regions while maintaining structural integrity. Additionally, the scalability of the method was demonstrated through the successful fabrication of large-area films (10 cm × 10 cm) and prototype electrochromic devices.
研究领域:
材料科学
·
电化学
·
光学材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）