Diffusion‐Triggered Synthesis of Mg₂Si Based on Infiltrated Silicon Structures in Molten Mg

Abstract

Magnesium silicide (Mg2Si) has many good properties and therefore shows a high application potential as thermoelectric material. Herein, the intermetallic layer growth behavior in the Mg–Si system is investigated. A process for synthesizing Mg2Si on the surface of open‐pore cellular Si structures is developed. The structure is fabricated by investment casting and followed by infiltration of magnesium. Subsequently, magnesium silicide is obtained by a two‐step heat treatment. Complete synthesis of Si to Mg2Si is achieved using a liquid–solid reaction between the liquid Mg and solid Si. The optimal heat treatment for the first step is at the eutectic temperature of 950 °C and for a duration of 120 min. The second treatment is at 1150 °C, slightly above the melting point of Mg2Si, and the remaining Si is synthesized. The resulting microstructures are analyzed using a scanning electron microscope (SEM) and energy‐dispersive spectroscopy (EDS).