The initial SnO powder was purchased from a commercial supplier, Alfa Aesar (99.9%). To reduce the powder agglomerate size, the weight ratio of the 1 SnO powder and 5 alumina grinding beads was mixed by a vibratory ball milling for 24 hours with ethanol followed by overnight drying at 80 °C. After the beads were removed, the dried powder was then ground using a pestle and mortar to shear any lumps formed during the previous ethanol drying process. Note that the initial powder was also used in this study to determine the particle size effects on density, microstructure, and thermoelectric properties.