Carbon nanotube (CNT)-reinforced TiNi matrix composites were synthesized by spark plasma sintering (SPS) employing elemental powders.The phase structure,morphology and transformation behaviors were studied.It was foun...Carbon nanotube (CNT)-reinforced TiNi matrix composites were synthesized by spark plasma sintering (SPS) employing elemental powders.The phase structure,morphology and transformation behaviors were studied.It was found that thermoelastic martensitic transformation be-haviors could be observed from the samples sintered above 800 ℃ even with a short sintering time (5min),and the transformation tempera-tures gradually increased with increasing sintering temperature because of more Ti-rich TiNi phase formation.Although decreasing the sin-tering temperature and time to 700 ℃ and 5min could not protect defective MWCNTs from reacting with Ti,still-perfect MWCNTs re-mained in the specimens sintered at 900 ℃.This method is expected to supply a basis for preparing CNT-reinforced TiNi composites.展开更多
Liquid ball-milling dispersant method was used to prepare the ZrO2-doped carbon laminations from mesocarbon microbeads（MCMBs）. After sintering at 1 300 ℃ in nitrogen atmosphere, the effect of ZrO2 concentration on ...Liquid ball-milling dispersant method was used to prepare the ZrO2-doped carbon laminations from mesocarbon microbeads（MCMBs）. After sintering at 1 300 ℃ in nitrogen atmosphere, the effect of ZrO2 concentration on sintering behavior, electric conductivity as well as bending strength of the carbon laminations was investigated in detail. The results showed that the volumetric shrinkage rate of the carbon laminations decreased from 38.2% to 30.9% when the ZrO2 concentration in raw materials varied from 0 to 16 wt%. Compared with undoped carbon lamination, the samples had high-electric conductivity and excellent bending strength in all cases. The electric conductivity achieved the maximum value of 225 S/cm, and the bending strength of the carbon lamination was 119.24 MPa for a concentration of 8 wt% ZrO2 in raw materials. In addition, the electric conductivity and bending strength reducing were observed when the ZrO2 concentration was higher than 8 wt%. The catalytic effect on graphitization for the carbon laminations was the most effective when the ZrO2 concentration was set at 8 wt% in raw materials.展开更多
Aqueous zinc batteries with low cost and inherent safety are considered to be the most promising energy storage devices.However,they suffer from poor cycling stability and low coulombic efficiencies caused by the adve...Aqueous zinc batteries with low cost and inherent safety are considered to be the most promising energy storage devices.However,they suffer from poor cycling stability and low coulombic efficiencies caused by the adverse zinc dendrites on the anodes during the discharging/charging processes.Chitosan is a kind of natural amino polysaccharide,which is rich in nitrogen and carbon.When sintered at high temperatures,carbon membranes have been achieved with excellent conductivity and graphitization degree,which could enhance the ability to induce zinc ion uniform deposition to some extent.In this work,a type of carbon membrane using chitosan as raw materials has been fabricated by sintering,and then assembled as the protect layers in aqueous zinc batteries.The results show that the samples could retain smoother surfaces when adopting the sintering temperature of 800℃,and the assembled batteries are able to achieve about 700 h at a current density of 0.25m A·cm^(-2),which is far longer than those of the similar batteries without any carbon membranes.展开更多
A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and t...A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and the baking process was thoroughly investigated.Compared with coated sand prepared by the hot method,the cold method yields a more uniform and complete resin film on the sand's surface,resulting in enhanced tensile strength and accuracy.Additionally,the cold method requires a lower binder content to meet the same strength requirements,thereby minimizing gas evolution,reducing porosity defects,and ultimately improving casting quality.The coated sand samples prepared through the cold method exhibit superior accuracy,with a size error of within±0.4 mm.In contrast,the coated sand samples prepared by the hot method display a lower accuracy,with an average negative error of 2.1993 mm.The highest tensile strength could be attained by controlling the baking temperature within a suitable range(180-190°C),which can effectively reduce the generation of gas,thus contributing to improved overall performance.展开更多
基金financially supported by Natural Science Foundation of China (No.51071059 and No.50971052)the Fundamental Research Funds for the Central Universities (No.HIT.KLOF.2010005)
文摘Carbon nanotube (CNT)-reinforced TiNi matrix composites were synthesized by spark plasma sintering (SPS) employing elemental powders.The phase structure,morphology and transformation behaviors were studied.It was found that thermoelastic martensitic transformation be-haviors could be observed from the samples sintered above 800 ℃ even with a short sintering time (5min),and the transformation tempera-tures gradually increased with increasing sintering temperature because of more Ti-rich TiNi phase formation.Although decreasing the sin-tering temperature and time to 700 ℃ and 5min could not protect defective MWCNTs from reacting with Ti,still-perfect MWCNTs re-mained in the specimens sintered at 900 ℃.This method is expected to supply a basis for preparing CNT-reinforced TiNi composites.
基金Funded by the Foundation of Jiangsu Key Laboratory of Fine Petrochemical Engineering
文摘Liquid ball-milling dispersant method was used to prepare the ZrO2-doped carbon laminations from mesocarbon microbeads（MCMBs）. After sintering at 1 300 ℃ in nitrogen atmosphere, the effect of ZrO2 concentration on sintering behavior, electric conductivity as well as bending strength of the carbon laminations was investigated in detail. The results showed that the volumetric shrinkage rate of the carbon laminations decreased from 38.2% to 30.9% when the ZrO2 concentration in raw materials varied from 0 to 16 wt%. Compared with undoped carbon lamination, the samples had high-electric conductivity and excellent bending strength in all cases. The electric conductivity achieved the maximum value of 225 S/cm, and the bending strength of the carbon lamination was 119.24 MPa for a concentration of 8 wt% ZrO2 in raw materials. In addition, the electric conductivity and bending strength reducing were observed when the ZrO2 concentration was higher than 8 wt%. The catalytic effect on graphitization for the carbon laminations was the most effective when the ZrO2 concentration was set at 8 wt% in raw materials.
基金financially supported by the National Natural Science Foundation of China (No.21571110)the NSF of Zhejiang province,China (No.LY18B010003)the Ningbo Municipal Natural Science Foundation (No.2022J096)。
文摘Aqueous zinc batteries with low cost and inherent safety are considered to be the most promising energy storage devices.However,they suffer from poor cycling stability and low coulombic efficiencies caused by the adverse zinc dendrites on the anodes during the discharging/charging processes.Chitosan is a kind of natural amino polysaccharide,which is rich in nitrogen and carbon.When sintered at high temperatures,carbon membranes have been achieved with excellent conductivity and graphitization degree,which could enhance the ability to induce zinc ion uniform deposition to some extent.In this work,a type of carbon membrane using chitosan as raw materials has been fabricated by sintering,and then assembled as the protect layers in aqueous zinc batteries.The results show that the samples could retain smoother surfaces when adopting the sintering temperature of 800℃,and the assembled batteries are able to achieve about 700 h at a current density of 0.25m A·cm^(-2),which is far longer than those of the similar batteries without any carbon membranes.
基金This work was financially supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U1808216)the Shanxi Provincial Key Research and Development Project(2022ZDYF072).
文摘A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and the baking process was thoroughly investigated.Compared with coated sand prepared by the hot method,the cold method yields a more uniform and complete resin film on the sand's surface,resulting in enhanced tensile strength and accuracy.Additionally,the cold method requires a lower binder content to meet the same strength requirements,thereby minimizing gas evolution,reducing porosity defects,and ultimately improving casting quality.The coated sand samples prepared through the cold method exhibit superior accuracy,with a size error of within±0.4 mm.In contrast,the coated sand samples prepared by the hot method display a lower accuracy,with an average negative error of 2.1993 mm.The highest tensile strength could be attained by controlling the baking temperature within a suitable range(180-190°C),which can effectively reduce the generation of gas,thus contributing to improved overall performance.
