Abstract
The influence of ball milling followed by Spark Plasma Sintering (SPS) on the thermoelectric properties of the Cu15As30Te55 glass composition has been investi- gated by means of X‐ray diffraction, scanning electron microscopy, and differen- tial scanning calorimetry. The microstructure, composition, and thermal stability of the ball‐milled samples before and after SPS have been correlated with the electrical and thermal transport properties. Upon ball milling, a glass‐to‐glass transformation is evidenced for short ball‐milling times, followed by crystallization of the metastable β‐As2Te3 phase within the glassy matrix. This glass‐to‐glass transformation favors the occurrence of the β‐As2Te3 phase during the SPS pro- cess. A maximum figure of merit ZT of 0.29 at 400 K is obtained in the sample exhibiting the largest β‐As2Te3 crystalline fraction. This ZT value is twice as high as the value obtained for the glass‐ceramic sintered from non‐ball‐milled powder.