Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,a...Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.展开更多
Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high...Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”展开更多
Nano Research volume 13,pages1659–1667(2020)Cite this article 232 Accesses 3 Citations Metrics details Abstract 2D MXenes are highly attractive for achieving ultrafast and stable lithium/sodium storage due to their g...Nano Research volume 13,pages1659–1667(2020)Cite this article 232 Accesses 3 Citations Metrics details Abstract 2D MXenes are highly attractive for achieving ultrafast and stable lithium/sodium storage due to their good electric conductivity and abundant redox active sites.While,effective strategies for scalable preparation of oligolayered MXenes are still under exploration.Herein,oligolayered Ti3C2Tx MXene is successfully obtained after conventional synthesis of multilayered Ti3C2 and subsequent delamination process via an organic solvent of tetramethyl-ammonium hydroxide(TMAOH).Comprehensive electrochemical study reveals that surface-controlled redox reaction dominated the charge storage behavior of oligolayered Ti3C2Tx with fast reaction kinetics.Impressively,the obtained oligolayered Ti3C2Tx exhibits excellent lithium/sodium storage performance,featured for a high specific capacity of 330 mAhg^−1 at 1.0 Ag^−1 after 800 cycles for lithium storage and 280 mAhg^−1 at 0.5 Ag^−1 after 500 cycles for sodium storage.Such impressive performance will advance the development of oligolayered Ti3C2Tx based materials for lithium/sodium storage and even broaden their application into energy storage.展开更多
Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air ...Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air filter, seeking both high filtration efficiency and low pressure drop remains challenging. Here, we report a bio-inspired spindle-knot halloysite nanotube microsphere-incorporated nanofiber(HNM-NF) filter with the assembly and shape structures of the spider silk. The resulting HNM-NFs exhibit integrated properties of high surface energy, hydrophilicity and strong PM capture. The spindle-knot structures could shrink the outer pore size on two-dimensional(2 D) surface and construct the fluffy 3 D reticular architecture, facilitating high-efficiency air pollutant capture(>85.0%) while maintaining low resistance to airflow(~39 Pa). The spindle-knot construction method was applicable to various materials(i.e.,Al_(2)O_(3), ZnO and TiO_(2)) and volume production of the microsphere-incorporated NF cartridge. The diversified spindleknot construction will be valuable for adapting to meet different filtration requirements.展开更多
基金supported by the National Natural Science Foundation of China (No. 52374292)China Baowu Low Carbon Metallurgy Innovation Foundation, China (No. BWLCF202309)the Natural Science Foundation of Changsha City, China (No. KQ2208271)。
文摘Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.
基金National Natural Science Foundation of China(No.51774331)Funds for Nationsl&Local Joint Engineering Research Center of Mineral Salt Deep Utilization(No.SF202103).
文摘Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”
基金This work was supported by Science Research Initiation Fund of Central South University(No.202045012)Key Research and Development Program of Jiangxi Province(No.20181ACE50013)+1 种基金Fundamental Research Funds for the Central Universities of Central South University(No.2019zzts708)the National Natural Science Foundation of China(No.61705152).
文摘Nano Research volume 13,pages1659–1667(2020)Cite this article 232 Accesses 3 Citations Metrics details Abstract 2D MXenes are highly attractive for achieving ultrafast and stable lithium/sodium storage due to their good electric conductivity and abundant redox active sites.While,effective strategies for scalable preparation of oligolayered MXenes are still under exploration.Herein,oligolayered Ti3C2Tx MXene is successfully obtained after conventional synthesis of multilayered Ti3C2 and subsequent delamination process via an organic solvent of tetramethyl-ammonium hydroxide(TMAOH).Comprehensive electrochemical study reveals that surface-controlled redox reaction dominated the charge storage behavior of oligolayered Ti3C2Tx with fast reaction kinetics.Impressively,the obtained oligolayered Ti3C2Tx exhibits excellent lithium/sodium storage performance,featured for a high specific capacity of 330 mAhg^−1 at 1.0 Ag^−1 after 800 cycles for lithium storage and 280 mAhg^−1 at 0.5 Ag^−1 after 500 cycles for sodium storage.Such impressive performance will advance the development of oligolayered Ti3C2Tx based materials for lithium/sodium storage and even broaden their application into energy storage.
基金supported by the National Natural Science Foundation of China (21878341,51804343,41572036 and 51225403)the Natural Science Foundation of Hunan Province(2018JJ3670)the Key R&D Program of Hunan Province(2017GK2251)。
文摘Long-term air contamination and pollution challenges in particulate matter(PM) have raised fervent concerns for public health, e.g., the PM physical damage or the bacteria and virus carried by the PM. The desired air filter, seeking both high filtration efficiency and low pressure drop remains challenging. Here, we report a bio-inspired spindle-knot halloysite nanotube microsphere-incorporated nanofiber(HNM-NF) filter with the assembly and shape structures of the spider silk. The resulting HNM-NFs exhibit integrated properties of high surface energy, hydrophilicity and strong PM capture. The spindle-knot structures could shrink the outer pore size on two-dimensional(2 D) surface and construct the fluffy 3 D reticular architecture, facilitating high-efficiency air pollutant capture(>85.0%) while maintaining low resistance to airflow(~39 Pa). The spindle-knot construction method was applicable to various materials(i.e.,Al_(2)O_(3), ZnO and TiO_(2)) and volume production of the microsphere-incorporated NF cartridge. The diversified spindleknot construction will be valuable for adapting to meet different filtration requirements.
