Lamellar Ni3Si Microchannels and Ni3Si Micropore Arrays in Ni─Ni3Si Hypereutectic Alloys

Abstract

Lamellar Ni3Si microchannels and Ni3Si micropore arrays were fabricated in directionally solidified Ni–Ni3Si hypereutectic alloys by selective dissolution. Regular lamellar and rod-like structures were obtained at growth rates of 1–6 μm/s for the hypereutectic alloys. The dissolution of the lamellar or rod-like Ni phases while passivating the continuous Ni3Si matrix resulted in continuous microchannels or nanopore arrays in the Ni–Ni3Si hypereutectic alloys. During selective dissolution, SiO2 preferentially formed on the Ni3Si phase and retarded its dissolution. The width of the microchannel was 2.85 μm, and the micropore diameter was approximately 7.86 μm. The structural materials with narrow microchannels can be applied in the field of catalyst, microfiltration, and micro/nanostructure fabrication.