中文摘要：

以机械合金化法（MA）结合放电等离子烧结技术（SPS）制备了Bi_2S_3多晶块体热电材料.研究了MA过程中干磨转速、湿磨时间和湿磨介质对Bi_2S_3多晶热电材料电传输性能的影响.分析了样品的物相,观察了显微组织,测试了电传输性能和热传输性能.研究表明,以无水乙醇为湿磨介质时,随着湿磨时间的延长,出现了微量Bi_2O_3第二相,样品的晶粒尺寸减小,电阻率大幅增加,功率因子下降.以丙酮为湿磨介质时,虽然不存在微氧化反应,但是由于样品中存在大量孔洞,导致功率因子降低.425 r/min干磨15 h后未湿磨的样品在573 K取得最大的ZT值0.25,是目前文献报道的最高值.

英文摘要：

Bismuth sulfide（Bi_2S_2） polycrystalline bulks are fabricated by spark plasma sintering（SPS） combined with a mechanical alloying （MA） process.The electrical transport properties are investigated with a special emphasis on dry-milling speed,wet-milling time and mediums in MA process.The phase structure,the microstructure,and the electrical/thermal transport properties for the bulk samples are measured.The results suggest that the second Bi_2O_3 phase is formed because of the micro-oxidation when the wet medium is fixed to absolute ethyl alcohol,which refines the grain sizes and affects electrical transport properties of the bulk samples.Prolonging the wet-milling time in absolute ethyl alcohol causes the increase of resistivity and the decrease of the power factor.The electrical transport properties degrade due to the porous microstructure in bulk samples even without oxidization as the acetone is used as a milling medium. The largest ZT value 0.25 is obtained at 573 K for the samples dry-milled under 425 r/min for 15 h without wet-milling,which is the highest value in the reported values so far.