METALS AND MATERIALS INTERNATIONAL
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2021
·Vol. 27
·期 12
·5389-5398
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IF 3.642
Hong S. F.,Lu Z. C.,Liu Y. H.,He Q. M.,Jiang W.,Zeng M. Q.
Abstract Supersaturated solid–solutions in a W–Cr alloy system were fabricated by conventional milling and plasma milling. The different extension mechanisms of the solid solubility that were created by ball milling with and without discharge plasma were studied. The solid–solubility of Cr in W for the P-milling W–Cr alloy system was higher, which indicates that plasma milling promotes the formation of W(Cr) solid–solution more easily than conventional milling. According to Miedema’s model, in the W–Cr alloy system, the free-energy change to form a W(Cr) solid solution by plasma milling is reduced compared with conventional milling because of the heating effect of the discharge plasma. Therefore, a higher stored energy in the grain boundaries and dislocations of the W–Cr nanograins during plasma milling makes it easier to overcome the thermodynamic barrier in the formation of a solid–solution, when compared with conventional milling. Graphic Abstract
研究领域:
材料科学
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物理学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2021
·Vol. 45
·期 6
·8724-8734
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IF 5.164
Ningning He,Guilin Wei,Pan Wen,Wenhong Han,Chen Xu,Xiaoyan Shu,Fen Luo,Shunzhang Chen,Lan Wang,Yi Xie,Xirui Lu
Summary As a rapid sintering method, spark plasma sintering (SPS) process has been widely applied to immobilize nuclear waste. In this work, trialkyl phosphine oxides (TRPO) were immobilized by the mixture of Gd 2 O 3 and ZrO 2 with SPS proceedings at 1650°C in 3 minutes. X-ray diffraction results present that the solid solubility is 10 to 20 wt% and all the sintered samples show a fluorite structure. Raman spectroscopy results show that the order degree of structure decreases as waste content increases. The lattice parameters decrease with the increasing doped waste content indicating the success of waste immobilization. Densities decrease for the sample with higher waste content which mainly caused by the existence of pores. Scanning electron microscope-energy dispersive X-ray spectroscopy and backscattered electron results perform the microstructure of the sintered sample. Furthermore, the leaching test shows that the sample has a considerable chemical stability. This study confirmed the possibility of rapid consolidation of Gd 2 Zr 2 O 7 bulk, dense ceramic with up to 10 ~ 20 wt% of immobilized TRPO waste. Highlights Multi-nuclides waste was rapidly immobilized by Gd 2 Zr 2 O 7 via SPS process. Phase transition happened with enhanced doping content. Density results decreased with the higher waste content. The order degree of structure decreased as waste content increased. The sintered matrix represented considerable chemical stability.
研究领域:
材料科学
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核废料处理
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DOI
高影响因子
CERAMICS INTERNATIONAL
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2022
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IF 5.532
Guilin Wei,Xiaoyan Shu,Mingfen Wen,Yuexiang Lu,Tao Duan,Shunzhang Chen,Hexi Tang,Jing Chen,Faqin Dong,Yi Xie,Yang He,Xirui Lu
Nuclear waste generated from the nuclear industry should be safely treated because of its harmful effects on the environment and humans. In this study, the mechanism of the as-prepared Gd 2 Zr 2 O 7 for nuclear waste immobilization was investigated as an example in the simulation of waste immobilization under spark plasma sintering (SPS) conditions. The solid solubility limit of the waste in the sintered matrices was 45 mol% at 1725 °C and 1800 °C. The phase transformation from fluorite to pyrochlore could be detected owing to the increase in the ionic radius ratio when the waste was immobilized in the matrix structure. A high sintering temperature promotes transformation by increasing the orderliness of the matrix structure and destroying the crystalline structures to form an amorphous structure, results in a decrease in structural orderliness. Moreover, the leaching rates of Nd, at approximately 3.5 × 10 −8 g·m −2 ·d −1 at 42 d, demonstrated high chemical stability in the matrices doping with 45 mol% simulated nuclear waste. A mechanism is proposed in this study for treating radioactive waste using Gd 2 Zr 2 O 7 ceramic under SPS conditions.
研究领域:
材料科学
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环境科学
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核能工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yao Yang,Jianqiang Bi,Kangning Sun,Linjing Qiao,Yi Liu,Yonghan Li,Hongyi Wang,Yanjie Liang,Mengmeng Shang
The composition and synthesis approach of high entropy ceramics have significant influences on their microstructures and mechanical properties. A new (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 high entropy diboride ceramic with excellent mechanical properties was successfully prepared by spark plasma sintering (SPS) at a relatively “low temperature” (1800 °C) in this work. The effects of two mixing strategies, grinding and ball milling, on the solid solubility of the calcined powders were studied. Furthermore, the effects of these two mixing strategies on the phase and morphology of the calcined powders and the mechanical properties of the SPS sintered ceramics were analyzed. Experimental results indicated that, compared with a single solid solution phase within the high entropy boride powders obtained by ball milling, incomplete solid-solution presented in the high entropy boride powders obtained using grinding treatment. It promoted the solid-state diffusion and in-situ reaction of the diborides in the ceramics during the sintering process, thereby improving the densification and the hardness of the high entropy diboride ceramics. By grinding treatment, (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 high entropy ceramic with a relative density of 94% and a hardness of up to 25.34 ± 1.5 GPa at an indentation load of 9.8 N was obtained at 1800 °C. This work not only expanded the family of high-entropy diboride ceramics but also proved the advantage of grinding treatment in preparation of high entropy diboride ceramics.
研究领域:
材料科学
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陶瓷
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高熵合金
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DOI
高影响因子
CERAMICS INTERNATIONAL
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2023
·
IF 5.2
Moyu Liao,Xinli Yi,Zhongxu Dai,Hang Qin,Wenming Guo,Hanning Xiao
Three metal-organic frameworks including Ce-BDC, In-BDC and In/Ce-BDC and corresponding derived CuO/ZnO/In 2 O 3 /CeO 2 catalysts were prepared. The catalyst-loaded cordierite honeycomb ceramic supports were applied in a microreactor for hydrogen production via methanol steam reforming. The In/Ce-BDC-derived catalyst exhibited a methanol conversion rate of 100%, a hydrogen yield of 0.336 mol/h and an energy efficiency of 54% at 300 °C and an inlet methanol flow rate of 0.112 mol/h. Moreover, CO with content lower than 1.5% and catalytic stability of 30 h was recorded. The high specific surface area and superior redox property of the In/Ce-BDC-derived catalyst were characterized. The increased contents of oxygen vacancies and surface oxygen, in collaboration with the improved solid solubility of CuO and ZnO, were associated with the charge exchange induced by the strong interaction between In 2 O 3 and CeO 2 , leading to the excellent catalytic performance of the In/Ce-BDC-derived catalyst.
研究领域:
化学工程
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催化
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材料科学
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能源
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）