Preparation of Cobalt-Antimony Thermoelectric Film using Pulse Electrolysis in Ethylene Glycol-CoCl₂-SbCl₃ Non-Aqueous Solution

抄録

The preparation of cobalt-antimony thermoelectric film using pulse electrolysis was investigated in ethylene glycol (EG)-CoCl₂-SbCl₃ non-aqueous solutions at 393 K. The layered structures consisting of Co rich Co-Sb alloy layers and Sb rich Co-Sb alloy layers were obtained by applying alternately the potentials for electrodepositing the former, E_Co, and the latter, E_Sb, in the 90.0 mol%EG-9.09 mol%CoCl₂-0.91 mol%SbCl₃ bath, and were heat-treated at 673 K for 24 h in Ar gas atmosphere to prepare the Co-Sb alloy films with uniform composition. The composition of Co-Sb alloy film was found to be controlled by adjusting the ratio of applied duration at E_Co, t_Co, to one at E_Sb, t_Sb, in the potential rectangular wave used in the pulse electrolysis. At the (t_Sb / t_Co) ratio of 7.0, the Co-Sb alloy film with the composition of 26.1 mol%Co-73.9 mol%Sb was obtained after heat treatment. This alloy film was not the CoSb₃ single phase, but included it as constituent and exhibited a p-type thermoelectric conversion by the given temperature difference.