Creation of Highly Porous Material with a Hierarchical Structure by Sintering of Nickel Nanopowder Using Ammonium Bicarbonate as Space Holder

Abstract

The possibility of obtaining permeable highly porous materials based on nanopowders of nickel using ammonium bicarbonate as a space holder is shown. In the fabrication of porous samples, a sintering-evaporation process (SEP) was carried out, in which a thermally unstable pore former was decomposed and distilled from the compacts during preheating before sintering. The resulting highly porous nickel exhibits a pronounced hierarchical structure. The size of macropores formed by large particles of space holder reaches tens of microns, and pore walls consisting of thin layers of partially sintered nickel particles have a developed surface and include pores of submicron sizes. The permeability of the material is ensured by the fact that macropores are interconnected by windows of micron sizes. Strength characteristics of highly porous nickel based on nanopowders are at the level of the corresponding parameters of bulk porous materials obtained by sintering micron-size metal powders using pore-forming agents.