Carbon nanotubes were coated with a layer of nickel-cobalt-phosphorus （Ni-Co-P） alloy with different compositions of Ni/Co through electroless plating. The effects of the concentration ratio of Co^2＋ to Ni^2＋, bat...Carbon nanotubes were coated with a layer of nickel-cobalt-phosphorus （Ni-Co-P） alloy with different compositions of Ni/Co through electroless plating. The effects of the concentration ratio of Co^2＋ to Ni^2＋, bath temperature, and pH on deposition rate are discussed. The prepared carbon nanotubes covered with Ni-Co-P were characterized and analyzed by fieldemission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and a vibrating sample magnetometer. The results show that the deposition rate reached the maximum when the concentration ratio of Co^2＋ to Ni^2＋ is 1 and the pH is 9; the deposition rate increases with the increase of bath temperature. The measurements of the magnetic properties of the obtained carbon nanotubes covered with Ni-Co-P indicate that the magnetic properties greatly depend on the concentration ratio of Co^2＋ to Ni^2＋, and the magnetic saturation reaches the maximum value when the Co^2＋ to Ni^2＋ ratio is 1. In addition, there are two peaks in the coercivity curve at Co^2＋ to Ni^2＋ ratios of 1/2 and 4/1, while the two peaks in the magnetic conductivity curve are located at Co^2＋ to Ni^2＋ ratios of 1/4 and 4/1.展开更多
Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various tempera...Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various temperatures.Electrochemical reaction kinetic parameters were also studied with proper electrochemical techniques.The influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical simulation.The results show that,proper ball-milling with nickel powders is beneficial to electrochemical performance.The theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.展开更多
The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal. The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward ...The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal. The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward each other during brazing and react at the interface to form an inter-metallic AlCu 2Ti compound which joins two parts to produce a brazing joint with higher strength.展开更多
基金ACKNOWLEDGMENTS This work was supported by Project of Fundamental Research the National Major Nanomaterials and Nanostructures （No.2005CB623603） and the National Natural Science Foundation of China （No.10674138）.
文摘Carbon nanotubes were coated with a layer of nickel-cobalt-phosphorus （Ni-Co-P） alloy with different compositions of Ni/Co through electroless plating. The effects of the concentration ratio of Co^2＋ to Ni^2＋, bath temperature, and pH on deposition rate are discussed. The prepared carbon nanotubes covered with Ni-Co-P were characterized and analyzed by fieldemission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and a vibrating sample magnetometer. The results show that the deposition rate reached the maximum when the concentration ratio of Co^2＋ to Ni^2＋ is 1 and the pH is 9; the deposition rate increases with the increase of bath temperature. The measurements of the magnetic properties of the obtained carbon nanotubes covered with Ni-Co-P indicate that the magnetic properties greatly depend on the concentration ratio of Co^2＋ to Ni^2＋, and the magnetic saturation reaches the maximum value when the Co^2＋ to Ni^2＋ ratio is 1. In addition, there are two peaks in the coercivity curve at Co^2＋ to Ni^2＋ ratios of 1/2 and 4/1, while the two peaks in the magnetic conductivity curve are located at Co^2＋ to Ni^2＋ ratios of 1/4 and 4/1.
文摘Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various temperatures.Electrochemical reaction kinetic parameters were also studied with proper electrochemical techniques.The influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical simulation.The results show that,proper ball-milling with nickel powders is beneficial to electrochemical performance.The theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.
文摘The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal. The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward each other during brazing and react at the interface to form an inter-metallic AlCu 2Ti compound which joins two parts to produce a brazing joint with higher strength.
