In this study, single phase polycrystalline Zn 4 Sb 3 as well as 11 at.% Zn-rich Zn 4 Sb 3 alloy having ε-Zn 4 Sb 3 (majority phase) and Zn (minority phase) phases bulk samples produced by gas-atomization and subsequently consolidated by spark plasma sintering (SPS) process. The crystal structures were analyzed by X-ray diffraction (XRD) and cross-sectional microstructure were observed by the scanning electron microscopy (SEM). The internal grain microstructure of 11at.% Zn-rich Zn 4 Sb 3 powders shows lamellar structure. Relative density, Vickers hardness and crack lengths were measured to investigate the effect of sintering temperature of Zn 4 Sb 3 samples which are sintered at 653, 673 and 693 K. Relative density of the single phase bulk Zn 4 Sb 3 sample reached to 99.2% of its theoretical density. The micro Vickers hardness of three different sintering temperatures were found around 2.17 -2.236 GPa.

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In this paper, starting from the gas atomization powders, n-type Bi2Te3 thermoelectric alloys prepared via high energy ball milling and subsequently consolidated by hot extrusion. The effect of ball milling on the microstructure of Bi2Te3 alloys was studied. With increasing the milling time, from 3 min to 90 min, the particles were coarsening due to the agglomerated because of the high surface energy of the fine particles adhesive each other during the high energy ball milling. The preferential orientations of grains indicate that the extrusion process has the significant method to forcing the basal plane to orient preferentially in the extrusion direction were clearly observed by the TEM micrograph. The maximum electrical conductivity 6675.567 Ω−1m−1 measured at 100 °C temperature owing to the increasing of carrier concentration due to the donor defect formation and contamination occurred during the high energy ball milling at longer milling time (90 min).

The objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP) powder was studied in HCl, HNO 3 , and H 2 SO 4 acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1) valuable metals (In, Ag, Mg) were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H 2 O = 50:50); (2) the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3) the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.