p-Type PbTe Thermoelectric Bulk Materials with Nanograins Fabricated by Attrition Milling and Spark Plasma Sintering

This work reports a manufacturing process that combines attrition milling and spark plasma sintering (SPS) in the preparation of PbTe bulk materials with nanosize grains. The process involves milling raw PbTe ingots into nanocrystalline powders and subsequent compacting of these powders into dense bulk materials by spark plasma sintering. Sintered samples with relative densities of over 95% and grain sizes as small as 80 nm to 1 mu m were obtained through this process. The thermoelectric properties of the samples were measured and compared with those of raw ingots at temperatures from 300 K to 400 K to demonstrate the influence of grain size on thermoelectric properties. The results reveal that reducing the grain size improved thermoelectric performance.