Thermal and electrical Properties of Mg2Si layers prepared by plasma spraying method

    Magnesium silicide is a narrow band gap semiconductor with a face-centered cubic structure. It is a non-toxic material and as such, is a candidate thermoelectric material for operation in the temperature range from 500 to 800 K. In this paper, air plasma spraying (APS) was used to prepare Mg₂Si coating and its functional properties were evaluated to examine the coating’s feasibility as a thermoelectric power generator material. During spraying, in-flight particle temperature and velocity with different conditions were measured via DPV-2000 particle diagnostics system. The phase formation and morphology of Mg₂Si before and after spraying was investigated with X-ray diffraction and scanning electron microscopy. The Mg₂Si coatings were also characterized for their thermal and electrical conductivities. The results showed that the Mg₂Si coatings included Mg₂Si as the main phase with impurity phases MgO and Si, and had about half thermal conductivity of the bulk and reasonable electrical conductivity.