A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles （BPPs） of Cu, Al, Al65Cu20Fe15 alloy, Cu7oNi30 alloy and Fe50Si50 alloy were ga...A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles （BPPs） of Cu, Al, Al65Cu20Fe15 alloy, Cu7oNi30 alloy and Fe50Si50 alloy were gained by broadening the X-ray diffraction （XRD） peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the FesoSiso alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster structure of the liquid metal is similar to the structure of its crystal lattice.展开更多
Supported metal-group materials are commonly utilized as state-of-the-art catalysts in industry.Atomic-sites catalysts(ASCs)have attracted increasing attention in catalysis owing to their 100%atom efficiency and uniqu...Supported metal-group materials are commonly utilized as state-of-the-art catalysts in industry.Atomic-sites catalysts(ASCs)have attracted increasing attention in catalysis owing to their 100%atom efficiency and unique catalytic performances toward various reactions.In particular,atomic dispersion of bulk and nano metals has become the focus of research and development in the synthesis of ASCs.Over the past decade,burgeoning interests have been paid to atomic dispersion in ASCs and their applications in catalysis.However,to the best of our knowledge,the systematic summary and analysis of atomic dispersion were rarely reported.In this review,recently developed ASCs by atomic dispersion were discussed in terms of synthetic atmosphere,driving force,applications in thermal catalytic reactions.Perspectives related to challenges and directions as well as design strategies of ASCs in atomic dispersion were also provided.展开更多
Bulk metallic glass （BMG） formation was explored in the Fe-B-Si-Nb alloy system though combined use of the atomic cluster line approach and the minor alloying strategy. The basic ternary compositions in the Fe-B-Si ...Bulk metallic glass （BMG） formation was explored in the Fe-B-Si-Nb alloy system though combined use of the atomic cluster line approach and the minor alloying strategy. The basic ternary compositions in the Fe-B-Si system were determined by the intersection points of two cluster lines, namely, Fe-B cluster to Si and Fe-Si cluster to B. 3at% -4at% Nb was added to the quaternary Fe-B-Si-Nb alloy. The casting experiments revealed that good glass-forming ability （GFA） occurred at the （Fe73.4Si8.2B18.4）96Nb4 composition, and 3-mm diameter BMG samples were made. The glass transition temperature （Tg）, crystallization temperature （Tx）, and supercooled liquid region （△Tx=Tx-Tg） of this BMG were measured to be 866, 889, and 23 K, respectively. The BMG shows a high Vickers hardness of about Hv 1164, a Young＇s modulus of 180 GPa, and a good corrosion resistance in the solutions of 1 mol/L HCl and 3wt% NaCl.展开更多
Experiments of X-ray diffraction for liquid Cu70Ni30 alloy above and below its liquidus (1 230℃) have been carried out. By the analysis of experimental results, it is discovered that difference between structures of ...Experiments of X-ray diffraction for liquid Cu70Ni30 alloy above and below its liquidus (1 230℃) have been carried out. By the analysis of experimental results, it is discovered that difference between structures of liquid and undercooled Cu70Ni30 alloy is their cluster sizes. The correlation radius of cluster is 1.125 nm and the atom number of cluster is 403 at 1 250-1 400℃, and they are 1.3 nm and 704 respectively at the undercooled liquid state (1 200℃). The structure of liquid alloy is fee short order and its solid structure, fcc, is kept from liquid fcc short order.展开更多
基金supported by the National NaturalScience Foundation of China (Grant Nos. 50971083,50395101 and 50571052)
文摘A nanocrystal model for liquid metals and amorphous metals has been developed. With the nanocrystal model, the broadening peak profiles （BPPs） of Cu, Al, Al65Cu20Fe15 alloy, Cu7oNi30 alloy and Fe50Si50 alloy were gained by broadening the X-ray diffraction （XRD） peaks of a crystal lattice. By comparing the BPPs with the XRD intensity curves measured on the liquid metals, it is found that the BPPs are closely in agreement with the XRD intensity curves, respectively, except the FesoSiso alloy. Therefore, the nanocrystal model can be used to determine if the atomic cluster structure of the liquid metal is similar to the structure of its crystal lattice.
基金Japan Society of Promotion of Science(JSPS)(Nos.P21354 and P22049).
文摘Supported metal-group materials are commonly utilized as state-of-the-art catalysts in industry.Atomic-sites catalysts(ASCs)have attracted increasing attention in catalysis owing to their 100%atom efficiency and unique catalytic performances toward various reactions.In particular,atomic dispersion of bulk and nano metals has become the focus of research and development in the synthesis of ASCs.Over the past decade,burgeoning interests have been paid to atomic dispersion in ASCs and their applications in catalysis.However,to the best of our knowledge,the systematic summary and analysis of atomic dispersion were rarely reported.In this review,recently developed ASCs by atomic dispersion were discussed in terms of synthetic atmosphere,driving force,applications in thermal catalytic reactions.Perspectives related to challenges and directions as well as design strategies of ASCs in atomic dispersion were also provided.
基金supported by the National Natural Science Foundation of China (Nos50901012 and 50631010)the National Basic Research Priorities Program of China (No2007CB613902)
文摘Bulk metallic glass （BMG） formation was explored in the Fe-B-Si-Nb alloy system though combined use of the atomic cluster line approach and the minor alloying strategy. The basic ternary compositions in the Fe-B-Si system were determined by the intersection points of two cluster lines, namely, Fe-B cluster to Si and Fe-Si cluster to B. 3at% -4at% Nb was added to the quaternary Fe-B-Si-Nb alloy. The casting experiments revealed that good glass-forming ability （GFA） occurred at the （Fe73.4Si8.2B18.4）96Nb4 composition, and 3-mm diameter BMG samples were made. The glass transition temperature （Tg）, crystallization temperature （Tx）, and supercooled liquid region （△Tx=Tx-Tg） of this BMG were measured to be 866, 889, and 23 K, respectively. The BMG shows a high Vickers hardness of about Hv 1164, a Young＇s modulus of 180 GPa, and a good corrosion resistance in the solutions of 1 mol/L HCl and 3wt% NaCl.
文摘Experiments of X-ray diffraction for liquid Cu70Ni30 alloy above and below its liquidus (1 230℃) have been carried out. By the analysis of experimental results, it is discovered that difference between structures of liquid and undercooled Cu70Ni30 alloy is their cluster sizes. The correlation radius of cluster is 1.125 nm and the atom number of cluster is 403 at 1 250-1 400℃, and they are 1.3 nm and 704 respectively at the undercooled liquid state (1 200℃). The structure of liquid alloy is fee short order and its solid structure, fcc, is kept from liquid fcc short order.
