[21p-S223-1~17] 13.2 Exploratory Materials, Physical Properties, Devices

[21p-S223-14] Energetic consideration of compounds formed at Mg₂Si-Ni electrode

〇Yoji Imai¹, Hiroharu Sugawara², Yoshihisa Mori³, Shigeyuki Nakamura⁴, Ken-ichi Takarabe³ (1.AIST, 2.Tokyo Metro. Univ., 3.Okayama Univ. Sci., 4.Tsuyama Natl. Col. Tech.)

Keywords:Mg-Ni-Si ternary alloys,electronic energy calculation

Mg₂Si has attracted much attention as one of the eco-friendly thermoelectric semiconductors. Ni is usually used as an electrode to constitute thermoelectric energy-conversion device and authors have tried to obtain the unified device by a plasma sintering method using Mg₂Si-Ni powder. It became clear that there was a boundary layer consisting of Ni, Mg and Si and this layer is composed of omega (or, nu) - phase, eta-phase, and the phase with the MgNi₂- type structure which appear in the Mg-Ni-Si phase diagram by using electron beam diffraction method. However, the detailed structures of these phases such as occupancy of crystallographic sites by constituent atoms are not known.
In this report, we estimated the crystal structure of these phases using an energy optimization method and tried to clear the properties of these phases.