The hierarchical BiOCl_(x)Br_(1–x)was synthesized by a simple solvothermal method.The samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),UV-visible diffuse reflect...The hierarchical BiOCl_(x)Br_(1–x)was synthesized by a simple solvothermal method.The samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),UV-visible diffuse reflectance spectroscopy(UV-vis DRS)and Brunauer-Emmett-Teller adsorption method.Compared to pure BiOCl or BiOBr,the BiOCl_(x)Br_(1–x)solid solution has enhanced photocatalytic degradation activity for rhodamine B.This phenomenon can be explained to the hierarchical structure,lager specific surface area and appropriate energy gap of the obtained BiOCl_(x)Br_(1–x)solid solution.The renewability and stability of photocatalyst were determinated and a possible mechanism of photocatalytic degradation was also proposed.展开更多
In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in pr...In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.展开更多
The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersa...The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersaturated solid solution.MA significantly decreased the lamellar spacing between particles,thus reducing the diffusion distance of solution atoms.Moreover,it caused a number of crystalline defects,which further promoted the solution diffusion.Subsequently,the MA-processed powder was consolidated into Fe-Zn part by laser sintering,which involved a partial melting/rapid solidification mechanism and retained the original supersaturated solid solution.Results proved that the Fe-Zn alloy became more susceptible with a lowered corrosion potential,and thereby an accelerated corrosion rate of(0.112±0.013)mm/year.Furthermore,it also exhibited favorable cell behavior.This work highlighted the advantage of MA combined with laser sintering for the preparation of Fe-Zn implant with improved degradation performance.展开更多
Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into ...Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into W through mechanical alloying. XRD analysis shows that after 50 h of ball milling, the diffraction peak of Al completely disappears and W(Al60) super-saturated solid solution powder is obtained. Further observation by HAADF and HRTEM reveals that the W(Al60) super-saturated solid solution powder is a mixture of solid solution and amorphous phase. Based on the good thermal stability of W(Al60) alloy powder below 1000℃, W(Al60)-Al composite was synthesized by hot pressing process.Impact initiation experiments suggest that the W(Al60)-Al composite has excellent reaction characteristics, and multiple types of tungsten oxides are detected in the reaction products, showing that the modified W is combustible in air. Due to the combustion of tungsten, the energy release rate of the W(Al60)-Al composite at speed of 1362 m/s reaches 2.71 kJ/g.展开更多
Ab initio calculations are used to understand the fundamental mechanism of the solid solution softening/hardening of the Mo-binary system.The results reveal that the Mo-Ti,Mo-Ta,Mo-Nb,and Mo-W interactions are primari...Ab initio calculations are used to understand the fundamental mechanism of the solid solution softening/hardening of the Mo-binary system.The results reveal that the Mo-Ti,Mo-Ta,Mo-Nb,and Mo-W interactions are primarily attractive with negative heats of formation,while the interactions of Mo-Re,and Mo-Zr would be mainly repulsive with positive heats of formation.It is also shown that the addition of Re and Zr would cause the solid solution softening of Mo by the decrease of the unstable stacking fault energy and the increase of ductility.On the contrary,the elements of W,Ta,Ti,and Nb could bring about the solid-solution hardening of Mo through the impediment of the slip of the dislocation and the decrease of ductility.Electronic structures indicate that the weaker/stronger chemical bonding due to the alloying elements should fundamentally induce the solid solution softening/hardening of Mo.The results are discussed and compared with available evidence in literatures,which could deepen the fundamental understanding of the solid solution softening/hardening of the binary metallic system.展开更多
After diffusion couples were annealed at 260-360 ℃, the concentration profiles of Zn element were measured by EPMA. It has been first quantitatively determined by Matano method that the interdiffusion coefficient in ...After diffusion couples were annealed at 260-360 ℃, the concentration profiles of Zn element were measured by EPMA. It has been first quantitatively determined by Matano method that the interdiffusion coefficient in A1-Zn fee solid solution containing high Zn contents is remarkably decreased due to the small addition of Cu. Also, the interdiffusion coefficient in A1-Zn fee solid solution clearly increases with the increasing of Zn concentration. The interdiffusion activity energy remarkably decreases with the increasing of Zn contents. On the other hand, the interdiffusion activity energy markedly increases due to the small addition of Cu in the A1 Zn fcc solid solution containing high Zn contents.展开更多
An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded mo...An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction(XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl_2 film due to Cl ions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg_(17)Al_(12) phase containing experimental alloys. The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg_2 Pb and Mg_(17)Al_(12) somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.展开更多
基金Project(2016TP1007)supported by the Hunan Provincial Science and Technology Plan Project,China
文摘The hierarchical BiOCl_(x)Br_(1–x)was synthesized by a simple solvothermal method.The samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),UV-visible diffuse reflectance spectroscopy(UV-vis DRS)and Brunauer-Emmett-Teller adsorption method.Compared to pure BiOCl or BiOBr,the BiOCl_(x)Br_(1–x)solid solution has enhanced photocatalytic degradation activity for rhodamine B.This phenomenon can be explained to the hierarchical structure,lager specific surface area and appropriate energy gap of the obtained BiOCl_(x)Br_(1–x)solid solution.The renewability and stability of photocatalyst were determinated and a possible mechanism of photocatalytic degradation was also proposed.
基金Project(2009BB4228) supported by the Natural Science Foundation of Chongqing City,ChinaProject(CK2010Z09) supported by the Research Foundation of Chongqing University of Science and Technology,China
文摘In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.
基金Projects(51935014,82072084,81871498)supported by the Natural Science Foundation of ChinaProjects(20192ACB20005,2020ACB214004)supported by the Jiangxi Provincial Natural Science Foundation of China+4 种基金Project(20201BBE51012)supported by the Provincial Key R&D Projects of Jiangxi Province,ChinaProject(2018)supported by the Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme,ChinaProject(2017RS3008)supported by Hunan Provincial Science and Technology Plan,ChinaProject supported by the Open Research Fund of Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology,ChinaProject(2020M682114)China Postdoctoral Science Foundation。
文摘The slow degration of iron limits its bone implant application.The solid solution of Zn in Fe is expected to accelerate the degradation.In this work,mechanical alloying(MA)was used to prepare Fe-Zn powder with supersaturated solid solution.MA significantly decreased the lamellar spacing between particles,thus reducing the diffusion distance of solution atoms.Moreover,it caused a number of crystalline defects,which further promoted the solution diffusion.Subsequently,the MA-processed powder was consolidated into Fe-Zn part by laser sintering,which involved a partial melting/rapid solidification mechanism and retained the original supersaturated solid solution.Results proved that the Fe-Zn alloy became more susceptible with a lowered corrosion potential,and thereby an accelerated corrosion rate of(0.112±0.013)mm/year.Furthermore,it also exhibited favorable cell behavior.This work highlighted the advantage of MA combined with laser sintering for the preparation of Fe-Zn implant with improved degradation performance.
基金supported by the National Natural Science Foundation of China, [Award number: 11972372] and [Award number: U20A20231]。
文摘Element W can effectively improve the density of energetic structural materials. However, W is an inert element and does not combust in air. To change the reaction characteristics of W, 60 at.% Al was introduced into W through mechanical alloying. XRD analysis shows that after 50 h of ball milling, the diffraction peak of Al completely disappears and W(Al60) super-saturated solid solution powder is obtained. Further observation by HAADF and HRTEM reveals that the W(Al60) super-saturated solid solution powder is a mixture of solid solution and amorphous phase. Based on the good thermal stability of W(Al60) alloy powder below 1000℃, W(Al60)-Al composite was synthesized by hot pressing process.Impact initiation experiments suggest that the W(Al60)-Al composite has excellent reaction characteristics, and multiple types of tungsten oxides are detected in the reaction products, showing that the modified W is combustible in air. Due to the combustion of tungsten, the energy release rate of the W(Al60)-Al composite at speed of 1362 m/s reaches 2.71 kJ/g.
基金Project(51801129)supported by the National Natural Science Foundation of ChinaProject supported by the State Key Laboratory of Powder Metallurgy,China。
文摘Ab initio calculations are used to understand the fundamental mechanism of the solid solution softening/hardening of the Mo-binary system.The results reveal that the Mo-Ti,Mo-Ta,Mo-Nb,and Mo-W interactions are primarily attractive with negative heats of formation,while the interactions of Mo-Re,and Mo-Zr would be mainly repulsive with positive heats of formation.It is also shown that the addition of Re and Zr would cause the solid solution softening of Mo by the decrease of the unstable stacking fault energy and the increase of ductility.On the contrary,the elements of W,Ta,Ti,and Nb could bring about the solid-solution hardening of Mo through the impediment of the slip of the dislocation and the decrease of ductility.Electronic structures indicate that the weaker/stronger chemical bonding due to the alloying elements should fundamentally induce the solid solution softening/hardening of Mo.The results are discussed and compared with available evidence in literatures,which could deepen the fundamental understanding of the solid solution softening/hardening of the binary metallic system.
文摘After diffusion couples were annealed at 260-360 ℃, the concentration profiles of Zn element were measured by EPMA. It has been first quantitatively determined by Matano method that the interdiffusion coefficient in A1-Zn fee solid solution containing high Zn contents is remarkably decreased due to the small addition of Cu. Also, the interdiffusion coefficient in A1-Zn fee solid solution clearly increases with the increasing of Zn concentration. The interdiffusion activity energy remarkably decreases with the increasing of Zn contents. On the other hand, the interdiffusion activity energy markedly increases due to the small addition of Cu in the A1 Zn fcc solid solution containing high Zn contents.
基金Project supported by 2015 Shandong Provincal Fund for Outstanding Talent Group,China
文摘An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction(XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl_2 film due to Cl ions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg_(17)Al_(12) phase containing experimental alloys. The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg_2 Pb and Mg_(17)Al_(12) somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.
