Formation of Fine Metal Particles with Etching Pits by Barrel Anodic Etching

Abstract

Porous Al particles with etching pits on their surfaces were produced by anodic etching of Al particles placed inside a rotating barrel. In this method, electrical current flows through the Al particles as they contact a Pt plate at the bottom of the barrel, causing anodic etching of their surfaces. The structure of the etching pits formed on the Al particle surfaces could be controlled by varying the current and electrolysis time. Furthermore, using an electrolyte containing a surfactant prevented particle flotation and enabled the formation of etching pits on Al surfaces with particle sizes smaller than 5 μm. Porous Mg particles can also be produced by performing barrel anodic etching using Mg particles as the starting material. The porous particles obtained using this method are expected to have various applications, such as in sensors, catalyst supports, and batteries.

Graphical Abstract

SEM images of porous Al particles with a diameter of 300 μm.