High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detecto...High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.展开更多
Precipitation strengthening is a crucial microscopic mechanism for enhancing the strength of magnesium alloys. In order to elucidate the influence of precipitation on the microscopic deformation mechanisms and macrosc...Precipitation strengthening is a crucial microscopic mechanism for enhancing the strength of magnesium alloys. In order to elucidate the influence of precipitation on the microscopic deformation mechanisms and macroscopic mechanical response of magnesium alloys under cyclic loading conditions, we employed a crystal plasticity model to analyze the stress-strain curves, specific crystal plane diffraction intensities, and the temporal evolution of various microscopic deformation mechanisms and twinning volume fractions for an extruded magnesium alloy, AXM10304, containing coherent precipitates. The research findings indicate that precipitation does not fundamentally alter the microscopic mechanisms of this alloy. However, it hinders twinning during the compression stage, mildly promotes detwinning during the tension stage, and enhances tension secondary hardening by elevating the difficulty of activation of the prismatic slip.展开更多
In-situ observation of microstructural evolution during heating and soaking process was carded out for a high nickel steel using HTCLSM. Dark phases were observed when soaking at 900℃. Results showed that the number ...In-situ observation of microstructural evolution during heating and soaking process was carded out for a high nickel steel using HTCLSM. Dark phases were observed when soaking at 900℃. Results showed that the number of the dark phases culminated in about 50 s during soaking at 900℃. With the increase of soaking time the area proportion of the dark phases increased and reached the maximum value in about 3 min, When temperature rose from 900 ℃, the dark phases remained steady initially, but started to dissolve into the matrix at about 1 060 ℃ and completely disappeared at 1 132℃. When the specimen soaked at 900 ℃ was cooled down to room temperature （RT）, the dark phases kept stable. Energy spectrum analysis results showed that the dark phases contained much more Cr and Mn elements than the matrix and,were also rich in V. Tensile test results showed that the dark phase strengthened the steel with the maximum tensile strength obtained after soaking at 900 ℃ for 3 minutes.展开更多
Proper utilization of the FeSO_4-7H_2O waste slag generated from TiO_2 industry is an urgent need,and Fe_3O_4 particles are currently being widely used in the wastewater flocculation field.In this work,magnetite was r...Proper utilization of the FeSO_4-7H_2O waste slag generated from TiO_2 industry is an urgent need,and Fe_3O_4 particles are currently being widely used in the wastewater flocculation field.In this work,magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant.Under optimum conditions,the obtained spherical magnetite particles are well crystallized with a Fe_3O_4 purity of 88.78%,but apt to aggregate with a median particle size of 1.83 μm.Magnetic measurement reveals the obtained Fe_3O_4 particles are soft magnetic with a saturation magnetization of 81.73 A·m^2/kg.In addition,a highly crystallized gypsum co-product is obtained in blocky or irregular shape.Predictably,this study would provide additional opportunities for future application of low-cost Fe_3O_4 particles in water treatment field.展开更多
以AgNO_(3)和Na_(2)CO_(3)为原料,聚乙二醇为辅助剂,采用水热法合成Ag_(2)CO_(3)光催化剂,再以Ag_(2)CO_(3)、AgNO_(3)与卤化钠为反应物,采用原位沉淀法制得卤化银/碳酸银复合光催化剂。分别用X射线衍射仪、扫描电镜、紫外-可见光谱仪...以AgNO_(3)和Na_(2)CO_(3)为原料,聚乙二醇为辅助剂,采用水热法合成Ag_(2)CO_(3)光催化剂,再以Ag_(2)CO_(3)、AgNO_(3)与卤化钠为反应物,采用原位沉淀法制得卤化银/碳酸银复合光催化剂。分别用X射线衍射仪、扫描电镜、紫外-可见光谱仪及荧光光谱仪等分析产物的结构、形貌和性能,并以甲基橙(MO)溶液为模拟染料溶液,对卤化银/碳酸银复合光催化剂的光催化活性和循环使用稳定性进行评价。结果表明:AgBr/Ag_(2)CO_(3)复合光催化剂(其中AgBr质量分数为90%)的光催化活性最佳;可见光光照5 min后,0.1 g AgBr/Ag_(2)CO_(3)复合光催化剂对MO的光催化降解率为96.6%,分别是单相AgBr、Ag_(2)CO_(3)、TiO2降解率的1.2倍、4.7倍和5.3倍;复合催化剂循环使用3次后对MO降解率达92.7%。卤化银/碳酸银复合光催化剂对甲基橙溶液的降解过程符合准一级动力学模型。展开更多
The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15%Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conducti...The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15%Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu-15%Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0.15% to 0.2% promotes the precipitation of Cr particles.展开更多
The effect of fine precipitates on the initiation and propagation of micro cracks and the length of dislocation free zone (DFZ) in a low alloy Cr Mo V steel was studied by in situ TEM observation for the specimens bot...The effect of fine precipitates on the initiation and propagation of micro cracks and the length of dislocation free zone (DFZ) in a low alloy Cr Mo V steel was studied by in situ TEM observation for the specimens both in embrittled and toughened conditions. The results show that in the embrittled specimen, dislocations emitted from the crack tip can easily slip by cutting through the precipitates and move away from the crack tip region, so that a long DFZ forms and the brittle fracture occurs via cleavage cracks initiating and propagating. The size of DFZ mainly depends upon the diameter and the interparticle distance of the precipitates in the matrix. In the toughened specimens, the size of DFZ extremely changes with the interparticle distance. Mobile dislocations are emitted from the crack tip and bypassing the particles. The interaction between the dislocations and the particles results in the dislocation pile up and tangle, leading to diminishing of the DFZ. The crack tip is easy to blunt or chang the propagating direction and the crack propagation shows a jagged path.展开更多
Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was...Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The Ca/P molar ratio was influenced by collagen addition—1.89 and 2.38 for samples without and with collagen, respectively. The WAXD pattern revealed better resolution and intensity besides higher crystallinity degree of the HA in the presence of collagen. The photomicrographs showed a strong influence of collagen on the HA morphology.展开更多
基金support from the Natural Science Foundation of Hubei Province(2020BED011)XPS characterizations and ICP-OES were carried out in the Analytical and Testing Center in HUST.
文摘High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.
文摘Precipitation strengthening is a crucial microscopic mechanism for enhancing the strength of magnesium alloys. In order to elucidate the influence of precipitation on the microscopic deformation mechanisms and macroscopic mechanical response of magnesium alloys under cyclic loading conditions, we employed a crystal plasticity model to analyze the stress-strain curves, specific crystal plane diffraction intensities, and the temporal evolution of various microscopic deformation mechanisms and twinning volume fractions for an extruded magnesium alloy, AXM10304, containing coherent precipitates. The research findings indicate that precipitation does not fundamentally alter the microscopic mechanisms of this alloy. However, it hinders twinning during the compression stage, mildly promotes detwinning during the tension stage, and enhances tension secondary hardening by elevating the difficulty of activation of the prismatic slip.
基金Shougang Research Institute of Technology for the financial support to this project
文摘In-situ observation of microstructural evolution during heating and soaking process was carded out for a high nickel steel using HTCLSM. Dark phases were observed when soaking at 900℃. Results showed that the number of the dark phases culminated in about 50 s during soaking at 900℃. With the increase of soaking time the area proportion of the dark phases increased and reached the maximum value in about 3 min, When temperature rose from 900 ℃, the dark phases remained steady initially, but started to dissolve into the matrix at about 1 060 ℃ and completely disappeared at 1 132℃. When the specimen soaked at 900 ℃ was cooled down to room temperature （RT）, the dark phases kept stable. Energy spectrum analysis results showed that the dark phases contained much more Cr and Mn elements than the matrix and,were also rich in V. Tensile test results showed that the dark phase strengthened the steel with the maximum tensile strength obtained after soaking at 900 ℃ for 3 minutes.
基金Project(2013A090100013)supported by the Special Project on the Integration of Industry,Education and Research of Guangdong Province,ChinaProject(201407300993)supported by the High-Tech Research and Development Program of Xinjiang Uygur Autonomous Region,China
文摘Proper utilization of the FeSO_4-7H_2O waste slag generated from TiO_2 industry is an urgent need,and Fe_3O_4 particles are currently being widely used in the wastewater flocculation field.In this work,magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant.Under optimum conditions,the obtained spherical magnetite particles are well crystallized with a Fe_3O_4 purity of 88.78%,but apt to aggregate with a median particle size of 1.83 μm.Magnetic measurement reveals the obtained Fe_3O_4 particles are soft magnetic with a saturation magnetization of 81.73 A·m^2/kg.In addition,a highly crystallized gypsum co-product is obtained in blocky or irregular shape.Predictably,this study would provide additional opportunities for future application of low-cost Fe_3O_4 particles in water treatment field.
文摘以AgNO_(3)和Na_(2)CO_(3)为原料,聚乙二醇为辅助剂,采用水热法合成Ag_(2)CO_(3)光催化剂,再以Ag_(2)CO_(3)、AgNO_(3)与卤化钠为反应物,采用原位沉淀法制得卤化银/碳酸银复合光催化剂。分别用X射线衍射仪、扫描电镜、紫外-可见光谱仪及荧光光谱仪等分析产物的结构、形貌和性能,并以甲基橙(MO)溶液为模拟染料溶液,对卤化银/碳酸银复合光催化剂的光催化活性和循环使用稳定性进行评价。结果表明:AgBr/Ag_(2)CO_(3)复合光催化剂(其中AgBr质量分数为90%)的光催化活性最佳;可见光光照5 min后,0.1 g AgBr/Ag_(2)CO_(3)复合光催化剂对MO的光催化降解率为96.6%,分别是单相AgBr、Ag_(2)CO_(3)、TiO2降解率的1.2倍、4.7倍和5.3倍;复合催化剂循环使用3次后对MO降解率达92.7%。卤化银/碳酸银复合光催化剂对甲基橙溶液的降解过程符合准一级动力学模型。
文摘The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15%Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu-15%Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0.15% to 0.2% promotes the precipitation of Cr particles.
文摘The effect of fine precipitates on the initiation and propagation of micro cracks and the length of dislocation free zone (DFZ) in a low alloy Cr Mo V steel was studied by in situ TEM observation for the specimens both in embrittled and toughened conditions. The results show that in the embrittled specimen, dislocations emitted from the crack tip can easily slip by cutting through the precipitates and move away from the crack tip region, so that a long DFZ forms and the brittle fracture occurs via cleavage cracks initiating and propagating. The size of DFZ mainly depends upon the diameter and the interparticle distance of the precipitates in the matrix. In the toughened specimens, the size of DFZ extremely changes with the interparticle distance. Mobile dislocations are emitted from the crack tip and bypassing the particles. The interaction between the dislocations and the particles results in the dislocation pile up and tangle, leading to diminishing of the DFZ. The crack tip is easy to blunt or chang the propagating direction and the crack propagation shows a jagged path.
文摘Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The Ca/P molar ratio was influenced by collagen addition—1.89 and 2.38 for samples without and with collagen, respectively. The WAXD pattern revealed better resolution and intensity besides higher crystallinity degree of the HA in the presence of collagen. The photomicrographs showed a strong influence of collagen on the HA morphology.
