Ni nanopowders were successfully prepared in large quantities by anodic arc discharged plasma method with homemade experimental apparatus in inert gas. The particle size, microstructure and morphology of the particles...Ni nanopowders were successfully prepared in large quantities by anodic arc discharged plasma method with homemade experimental apparatus in inert gas. The particle size, microstructure and morphology of the particles were characterized via X-ray diffractometry(XRD), transmission electron microscopy(TEM) and the corresponding selected area electron diffractometry(SAED). The specific surface area and pore parameters were investigated by nitrogen sorption isotherms at 77 K with Brunauer-Emmett-Teller(BET) equation and Barrett-Joyner-Halenda (BJH) method. The chemical compositions were determined by X-ray energy dispersive spectrometry (XEDS) and element analysis. The experimental results indicate that this method is convenient and effective, and the nanopowders with uniform size, higher purity, weakly agglomerated and spherical chain shape are gotten. The crystal structure of the samples is FCC structure as the bulk materials, the particle size distribution ranges from 20 to 70 nm, and the average particle size is about 46 nm obtained by TEM and confirmed by XRD and BET results. The specific surface area is 14.23 m^2/g, specific pore volume is 0.09 cm^3/g and average pore diameter is 23 nm.展开更多
Based on the thermodynamics and kinetics theory, a theoretical model was built to illuminate the formation of metal nanopowders by anodic arc discharging plasma method, and the mechanism of particle nucleation and gro...Based on the thermodynamics and kinetics theory, a theoretical model was built to illuminate the formation of metal nanopowders by anodic arc discharging plasma method, and the mechanism of particle nucleation and growth was investigated. In addition, the morphology, crystal structure, particle size and specific surface area of the nanopowders were characterized by X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET) adsorption, transmission electron microscopy(TEM) and the corresponding selected area electron diffraction(SAED). The experimental results indicate that the nanopowders prepared by this process have uniform size, high purity, single phase and spherical shape. The crystal structure is FCC structure, the same as that of the bulk materials; the specific surface area is 12 m2/g, the particle size distribution ranges from 30 to 90 nm with an average particle size of 67 nm which is obtained from TEM and confirmed from XRD and BET results.展开更多
The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized ...The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized by transmission election microscopy,Raman spectroscopy and X-ray diffractometry. The magnetic properties of the products were characterized with vibration sample magnetometer. The TEM results show that MWCNTs have little impurity and good particles size,and Fe/Co with high continuity encapsulaties in carbon nanotubes. The saturated magnetization(σs),remanence(σm) and coercivity(Hc) of the sample are 17.30 A/(m·kg),3.96 A/(m·kg) and 31 521.60 A/m,showing better ferromagnetism compared with the bulk Fe/Co. The optimal conditions in this case are as follows:a helium gas atmosphere of 6.0×104 Pa,an arc current of 70 A,a voltage drop of 24 V,a constant distance of about 2 mm between the anodes and cathode,metallic powder contents of Fe and Co of 15.0%(mass fraction) and 15.0%,respectively,and well cooled electrodes and collector. This process is a convenient and effective that Fe/Co particles can be encapsulated in MWCNTs.展开更多
基金Project(GS012 A52 047) supported by the Bureau of Science & Technology of Gansu Province China
文摘Ni nanopowders were successfully prepared in large quantities by anodic arc discharged plasma method with homemade experimental apparatus in inert gas. The particle size, microstructure and morphology of the particles were characterized via X-ray diffractometry(XRD), transmission electron microscopy(TEM) and the corresponding selected area electron diffractometry(SAED). The specific surface area and pore parameters were investigated by nitrogen sorption isotherms at 77 K with Brunauer-Emmett-Teller(BET) equation and Barrett-Joyner-Halenda (BJH) method. The chemical compositions were determined by X-ray energy dispersive spectrometry (XEDS) and element analysis. The experimental results indicate that this method is convenient and effective, and the nanopowders with uniform size, higher purity, weakly agglomerated and spherical chain shape are gotten. The crystal structure of the samples is FCC structure as the bulk materials, the particle size distribution ranges from 20 to 70 nm, and the average particle size is about 46 nm obtained by TEM and confirmed by XRD and BET results. The specific surface area is 14.23 m^2/g, specific pore volume is 0.09 cm^3/g and average pore diameter is 23 nm.
基金Project (3ZS042-B25-017) supported by the Natural Science Foundation of Gansu Province, China
文摘Based on the thermodynamics and kinetics theory, a theoretical model was built to illuminate the formation of metal nanopowders by anodic arc discharging plasma method, and the mechanism of particle nucleation and growth was investigated. In addition, the morphology, crystal structure, particle size and specific surface area of the nanopowders were characterized by X-ray diffraction(XRD), Brunauer-Emmett-Teller(BET) adsorption, transmission electron microscopy(TEM) and the corresponding selected area electron diffraction(SAED). The experimental results indicate that the nanopowders prepared by this process have uniform size, high purity, single phase and spherical shape. The crystal structure is FCC structure, the same as that of the bulk materials; the specific surface area is 12 m2/g, the particle size distribution ranges from 30 to 90 nm with an average particle size of 67 nm which is obtained from TEM and confirmed from XRD and BET results.
基金Project (ZS-011-A25-007) supported by the Natural Science Foundation of Gansu province, China
文摘The experimental apparatus by self-designed was used,Fe/Co particles encapsulated in multi-walled carbon nanotubes(MWCNTs) were prepared by the method of anodic arc discharging plasma. The products were characterized by transmission election microscopy,Raman spectroscopy and X-ray diffractometry. The magnetic properties of the products were characterized with vibration sample magnetometer. The TEM results show that MWCNTs have little impurity and good particles size,and Fe/Co with high continuity encapsulaties in carbon nanotubes. The saturated magnetization(σs),remanence(σm) and coercivity(Hc) of the sample are 17.30 A/(m·kg),3.96 A/(m·kg) and 31 521.60 A/m,showing better ferromagnetism compared with the bulk Fe/Co. The optimal conditions in this case are as follows:a helium gas atmosphere of 6.0×104 Pa,an arc current of 70 A,a voltage drop of 24 V,a constant distance of about 2 mm between the anodes and cathode,metallic powder contents of Fe and Co of 15.0%(mass fraction) and 15.0%,respectively,and well cooled electrodes and collector. This process is a convenient and effective that Fe/Co particles can be encapsulated in MWCNTs.
