The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on acti...The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.展开更多
Eighteen as-cast binary Mg-Ni, Mg-Mm and ternary Mg-Ni-Mm and Mg-Ni-TM （TM=transition metals （Cu, Zn, Mn and Co）; Mm = mischmetal containing Ce, La, Nd and Pr） alloys were hydrided by an electrochemical process to...Eighteen as-cast binary Mg-Ni, Mg-Mm and ternary Mg-Ni-Mm and Mg-Ni-TM （TM=transition metals （Cu, Zn, Mn and Co）; Mm = mischmetal containing Ce, La, Nd and Pr） alloys were hydrided by an electrochemical process to determine the alloys with the most potential for electrochemical hydrogen storage. The alloys were hydrided in a 6 mol/L KOH solution at 80 °C for 480 min and at 100 A/m2. To assess the electrochemical hydriding performance of alloys, maximum hydrogen concentrations, hydrogen penetration depths and total mass of absorbed hydrogen in the alloys were measured by glow discharge spectrometry. In addition, the structures and phase compositions of the alloys both before and after hydriding were studied by optical and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. It was determined that the highest total amount of hydrogen was absorbed by the Mg-25Ni-12Mm and Mg-26Ni （mass fraction, %） alloys. The maximum hydrogen concentrations in the Mg-25Ni-12Mm and Mg-26Ni alloys were 1.0% and 1.6%, respectively. The main hydriding product was the binary MgH2 hydride, and the ternary Mg2NiH4 hydride was also detected in the Mg-25Ni-12Mm alloy. The electrochemical hydriding parameters achieved are discussed in relation to the structures of alloys, alloying elements and hydriding mechanisms.展开更多
基金Project(5227010679)supported by the National Natural Science Foundation of China。
文摘The process of preparing anodic oxide film containing active sites and electroless nickel plating on highly active rare earth magnesium alloy was developed.The formation mechanism of electroless nickel plating on active anodic oxide film and the structure and properties of the composite coating were studied by several surface and electrochemical techniques.The results showed that Ag nanograins with an average size of 10 nm were embedded into the anodic oxide film with pores of 0.1−2μm.Ag nanoparticles provided a catalytic site for the deposition of Ni-B alloy,and the Ni crystal nucleus was first grown in horizontal mode and then in cylindrical mode.The corrosion potential of the composite coating increased by 1.37 V and the corrosion current reduced two orders of magnitude due to the subsequent deposition of Ni-P alloy.The high corrosion resistance was attributed to the misaligning of these micro defects in the three different layers and the amorphous structure of the Ni-P alloy in the outer layer.These findings provide a new idea for electroless nickel plating on anodic oxide film.
基金supported by the Czech Science Foundation(project no.P108/12/G043)
文摘Eighteen as-cast binary Mg-Ni, Mg-Mm and ternary Mg-Ni-Mm and Mg-Ni-TM （TM=transition metals （Cu, Zn, Mn and Co）; Mm = mischmetal containing Ce, La, Nd and Pr） alloys were hydrided by an electrochemical process to determine the alloys with the most potential for electrochemical hydrogen storage. The alloys were hydrided in a 6 mol/L KOH solution at 80 °C for 480 min and at 100 A/m2. To assess the electrochemical hydriding performance of alloys, maximum hydrogen concentrations, hydrogen penetration depths and total mass of absorbed hydrogen in the alloys were measured by glow discharge spectrometry. In addition, the structures and phase compositions of the alloys both before and after hydriding were studied by optical and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. It was determined that the highest total amount of hydrogen was absorbed by the Mg-25Ni-12Mm and Mg-26Ni （mass fraction, %） alloys. The maximum hydrogen concentrations in the Mg-25Ni-12Mm and Mg-26Ni alloys were 1.0% and 1.6%, respectively. The main hydriding product was the binary MgH2 hydride, and the ternary Mg2NiH4 hydride was also detected in the Mg-25Ni-12Mm alloy. The electrochemical hydriding parameters achieved are discussed in relation to the structures of alloys, alloying elements and hydriding mechanisms.
