Effect of different processing routes on the power factor of the filled skutterudite Smy(FexNi1-x)4Sb12 (x = 0.50-0.80; y = 0.12-0.53)

The effect of varying the applied pressure during the processing by spark plasma sintering (SPS) of samples belonging to the Smy(FexNi1-x)4Sb12 system has been investigated by evaluating the power factor of the obtained filled skutterudite. A strong dependence of both the electrical conductivity and the Seebeck coefficient on the applied pressure has been observed. The highest power factor was detected at different pressures for the different compositions, being the optimal value 180 MPa for the sample with x = 0.80, and 400 MPa for the samples with x = 0.50 and x = 0.63. Relying on the present results, a possible further improvement of power factor of samples with x = 0.50 and x = 0.63 by enhancing the applied pressure above 400 MPa cannot be excluded.