Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

摘要

In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N_2 adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at. percent Ni alloy consists of alpha-Al, NiAl_3 and Ni_2Al_3, while the melt spun Al-25 and 31.5 at. percent Ni alloys comprise NiAl_3 and Ni_2Al_3. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.