Freeze-Casting of Silicon

Fernando L. Reyes Tirado

An aqueous suspension of 5 vol% silicon (Si) nanoparticles was directionally solidified at substrate temperatures between -10 and -25 C, resulting in colonies of aligned pure ice dendrites separated by interdendritic Si particles packed walls. Channels are created by sublimation of the dendrites, and the surrounding Si walls are densified by sintering. The resulting Si foams exhibit a 76 2% macroporosity, with the width of the ice-templated channels and the Si walls decreasing with solidification temperature, from 106 to 60 m and from 34 to 17 m, respectively. Si walls show high surface roughness from inverse templating of short secondary ice dendrite arms.

Figure. 1. Longitudinal cross sections of ice templated Silicon.

Related Publications

  1. Tirado, F. L. R., Huang, J., & Dunand, D. C. (2017). Ice-templated silicon foams with aligned lamellar channels. MRS Communications, 7(4), 928-932.