Porous metallic structures by de-alloying microcrystalline melt-spun ternary Zn70(Sn,Bi)30

A rapid solidification method (melt-spinning technique) was applied to produce a series of Zn70Sn30 - xBix (x = 5,15,30) ribbons with homogeneous microcrystalline structure. All alloys contained ternary eutectics in a different amount depending on their overall composition, as Zn70Sn15Bi15 was characterized with maximum quantity of the ternary eutectic colonies. The as-quenched alloys in the form of ribbons were subjected to selective electrochemical dissolution (de-alloying), which resulted in mechanically stable three-dimensional porous structures. It was found that both, the morphology and size of the pores and ligaments depend on the initial alloys' composition and microstructure. The fine initial alloys microstructure (grain size < 200nm) produced by rapid solidification resulted in pores and ligaments in the nanometric range. The Bi-richest porous alloy revealed a morphology similar to that of human bones, while the porous alloys produced from Zn70Sn25Bi5 and Zn70Sn15Bi15 were characterized by a worm-like ligament structure. The results obtained pave the way for the formation of useful for practical applications porous structures (e.g., for ion batteries electrodes) by de-alloying microcrystalline eutectic alloys with a suitable phase composition.

Automated summary

A series of Zn70Sn30-xBix ribbons with homogeneous microcrystalline structure were produced using a rapid solidification method. Selective electrochemical dissolution resulted in mechanically stable three-dimensional porous structures, with the morphology and size of the pores and ligaments depending on the initial alloy composition and microstructure.