Investigation on the Dealloying Process of Mn75-xNi25Alx (x=0, 5, 10, 15, 20 at. %) Alloy Ribbons

Abstract

The main purpose of this study is to investigate the impact of alloy composition and different dealloying condition on the microstructure of the nanoporous Ni. In this paper, Mn75-xNi25Alx(x=0, 5, 10, 15, 20 at. %) alloy ribbons were prepared by single roller rotary quenching system and then further investigated by X-ray Diffraction (XRD). Corrosion resistance was evaluated by means of Tafel polarization. The nanoporous nickel was synthesized by selective dissolution of Mn and Al, which is known as dealloying. The corrosion parameters of dealloying process have been studied in detail. The alloy ribbon developed into amorphous when the Al content reached 15 at.%. According to the Icorr, the corrosion resistance of Mn-Ni-Al alloy ribbons increases with the addition of Al. The addition of Al element, especially when Al content is over 15 at. %, will hinder the dealloying process resulting in the destruction of the nanoporous structure. The dealloying time is also critical to the microstructure of nanoporous nickel obtained. It was found in this work that, during dealloying process, 90 min is insufficient for complete selective dissolution of the active component (Mn and Al). However, the overextended dealloying time of 1440 min time will cause the coarsening destruction of inner porous due to the diffusion of noble element (Ni).