The nanocrystalline Fe-Ni-Cr coatings were electrodeposited by using the pulse current technique.The SEM results showed that the coatings had a mixed morphology of small nodules and fine cauliflower structures at low ...The nanocrystalline Fe-Ni-Cr coatings were electrodeposited by using the pulse current technique.The SEM results showed that the coatings had a mixed morphology of small nodules and fine cauliflower structures at low current densities.Also,the Cr content was increased at expense of Fe and Ni contents at high current densities.XRD patterns confirmed that the pulse current density had a positive effect on the grain refinement.The results of vibrating sample magnetometer(VSM)measurements demonstrated that by increasing the current density,the saturation magnetization was decreased and the coercivity was increased due to the enhancement of Cr content and the reduction of the grain size.The friction coefficient and wear rate values were decreased by increasing the pulse current density.Also,both the adhesive and abrasive wear mechanisms were observed on the worn surfaces.The abrasive grooves and the amount of wear debris were decreased by increasing the pulse current density.展开更多
Nanocrystalline Ni-Fe FCC alloy coatings with Fe content of 1.3%-39%（mass fraction） were fabricated on the nickel substrates using a DC electrodeposition technique. The crystal structure, lattice strain, grain size ...Nanocrystalline Ni-Fe FCC alloy coatings with Fe content of 1.3%-39%（mass fraction） were fabricated on the nickel substrates using a DC electrodeposition technique. The crystal structure, lattice strain, grain size and lattice constant of the Ni-Fe alloy coatings were studied by X-ray diffraction technique. The chemical composition and surface morphology of the FCC Ni-Fe alloy coatings were investigated with the energy dispersive X-ray spectroscopy（EDS） and atomic force microscopy（AFM）. The results show that the Fe content of the Ni-Fe alloy coatings has a great influence on the preferred orientation, grain size, lattice constant and lattice strain. FCC Ni-Fe alloy coatings exhibit preferred orientations of（200） or（200）（111）. With an increase of Fe content, the preferred growth orientation of（200） plane is weakened gradually, while the preferred growth orientation of（111） increases. An increase of the Fe content in the range of 1.3%-25%（mass fraction） results in a significant grain refinement of the coatings. Increasing the Fe content beyond 25% does not decrease the grain size of FCC Ni-Fe alloys further. The lattice strain increases with increasing the Fe content in the FCC Ni-Fe alloys. Since the alloys with Fe content not less than 25% has similar grain size（~11 nm）, the increase in the lattice strain with the increase of Fe content cannot be attributed to the change in the grain size.展开更多
Electroless Ni-Fe-P alloy plating on the surface of CNTs was carded out with a bath using citrate salt and lactic acid as complex agents. We proposed a chemical reaction mechanism. The morphology, structure and chemic...Electroless Ni-Fe-P alloy plating on the surface of CNTs was carded out with a bath using citrate salt and lactic acid as complex agents. We proposed a chemical reaction mechanism. The morphology, structure and chemical composition of the Ni-Fe-P/CNTs were studied with the aid of a scanning electronic microscope （SEM）, X-ray diffraction （XRD） and an energy-dispersive X-ray spectral analysis （EDS）. The results show that through a correct pre-treatment and electroless plating, Ni-Fe-P/CNTs composite particles can be obtained. The optimum electroless plating parameters of 35-42℃ and pH of 8.5-9.7 were achieved. The as-plated Ni-Fe-P alloy is amorphous. After a heat treatment at 500℃ for 90 min in H2, the coating is transformed into crystalloid Ni3E Fe2NiP and （Fe,Ni）3R The Ni-Fe-P alloy coating on the surface of CNTs is smooth and unique. The amount of Ni on the surface （mass fraction） of the Ni-Fe-P/CNTs composite particles is 29.13%, that of Fe 3.19% and that of P 2.28%.展开更多
文摘The nanocrystalline Fe-Ni-Cr coatings were electrodeposited by using the pulse current technique.The SEM results showed that the coatings had a mixed morphology of small nodules and fine cauliflower structures at low current densities.Also,the Cr content was increased at expense of Fe and Ni contents at high current densities.XRD patterns confirmed that the pulse current density had a positive effect on the grain refinement.The results of vibrating sample magnetometer(VSM)measurements demonstrated that by increasing the current density,the saturation magnetization was decreased and the coercivity was increased due to the enhancement of Cr content and the reduction of the grain size.The friction coefficient and wear rate values were decreased by increasing the pulse current density.Also,both the adhesive and abrasive wear mechanisms were observed on the worn surfaces.The abrasive grooves and the amount of wear debris were decreased by increasing the pulse current density.
基金Project(51021063)supported by the National Natural Science Fund for Innovation Group of ChinaProject(2012M521540)supported by China Post Doctoral Science Foundation+1 种基金Project(2013RS4027)supported by the Post Doctoral Scientific Foundation of Hunan Province,ChinaProject(CSUZC2013023)supported by the Precious Apparatus Open Share Foundation of Central South University,China
文摘Nanocrystalline Ni-Fe FCC alloy coatings with Fe content of 1.3%-39%（mass fraction） were fabricated on the nickel substrates using a DC electrodeposition technique. The crystal structure, lattice strain, grain size and lattice constant of the Ni-Fe alloy coatings were studied by X-ray diffraction technique. The chemical composition and surface morphology of the FCC Ni-Fe alloy coatings were investigated with the energy dispersive X-ray spectroscopy（EDS） and atomic force microscopy（AFM）. The results show that the Fe content of the Ni-Fe alloy coatings has a great influence on the preferred orientation, grain size, lattice constant and lattice strain. FCC Ni-Fe alloy coatings exhibit preferred orientations of（200） or（200）（111）. With an increase of Fe content, the preferred growth orientation of（200） plane is weakened gradually, while the preferred growth orientation of（111） increases. An increase of the Fe content in the range of 1.3%-25%（mass fraction） results in a significant grain refinement of the coatings. Increasing the Fe content beyond 25% does not decrease the grain size of FCC Ni-Fe alloys further. The lattice strain increases with increasing the Fe content in the FCC Ni-Fe alloys. Since the alloys with Fe content not less than 25% has similar grain size（~11 nm）, the increase in the lattice strain with the increase of Fe content cannot be attributed to the change in the grain size.
基金Projects 20060359011 supported by the Doctoral Subject Foundation of the Ministry of Education of China103-037016 by the Technological Innovation Foundation of Hefei University of Technology
文摘Electroless Ni-Fe-P alloy plating on the surface of CNTs was carded out with a bath using citrate salt and lactic acid as complex agents. We proposed a chemical reaction mechanism. The morphology, structure and chemical composition of the Ni-Fe-P/CNTs were studied with the aid of a scanning electronic microscope （SEM）, X-ray diffraction （XRD） and an energy-dispersive X-ray spectral analysis （EDS）. The results show that through a correct pre-treatment and electroless plating, Ni-Fe-P/CNTs composite particles can be obtained. The optimum electroless plating parameters of 35-42℃ and pH of 8.5-9.7 were achieved. The as-plated Ni-Fe-P alloy is amorphous. After a heat treatment at 500℃ for 90 min in H2, the coating is transformed into crystalloid Ni3E Fe2NiP and （Fe,Ni）3R The Ni-Fe-P alloy coating on the surface of CNTs is smooth and unique. The amount of Ni on the surface （mass fraction） of the Ni-Fe-P/CNTs composite particles is 29.13%, that of Fe 3.19% and that of P 2.28%.
