熔体旋甩工艺对n型InSb化合物的微结构及热电性能的影响

采用新颖的熔体旋甩结合放电等离子烧结技术制备了单相InSb化合物，研究了熔体旋甩工艺对其微结构以及热电性能的影响. 结果表明，熔体旋甩得到的薄带自由面主要由300 nm—2 μm的小柱状晶组成，薄带接触面为非晶或精细纳米晶，薄带经烧结后得到了具有大量层状精细纳米结构的致密块体，尺寸约为40 nm. 与熔融+放电等离子体烧结制备样品相比，在测试温度范围内（300—700 K），试样的电导率略有下降，但Seebeck系数显著增加，热导率和晶格热导率显著降低，室温下晶格热导率降低幅度约为106%，700 K下晶格热导率的降低幅度达1664%，熔融+熔体旋甩+放电等离子体烧结制备的InSb化合物试样在700 K时其最大ZT值达到049，与熔融+放电等离子体烧结试样相比提高了29%. 关键词： 熔体旋甩 n型InSb化合物 微结构 热电性能

Effects of melt spinning process on microstructure and thermoelectric properties of n-type InSb compounds

The single-phase InSb compounds have been prepared by novel melt spinning(MS)technique combined with spark plasma sintering(SPS)method,and the effects of melt spinning process on their microstructure and thermoelectric transport properties have been investigated.The results show that the free surface of ribbon obtained by MS consists of cubic grains with the size of 0.3-2.0 μm.and the contact surface of ribbon obtained by MS amorphous-like phases or finer nanostructures have formed,and after SPS the highly dense bulk material with lots of fine layered nanostructure has been obtained of about 40 nm in dimensions.By comparing the bulk InSb material prepared by melting method combined with SPS(Melt+SPS sample)with the bulk InSb material obtained by melting method combined with MS and SPS(Melt +MS+SPS sample),we see that the MS process leads to a slight decrease in electrical conductivity,and an obvious increase in Seebeck coefficient,as well as a remarkable decrease in thermal conductivity and lattice thermal conductivity for bulk InSb in the testing temperature range of 300-700 K.At 300 K and 700 K,the lattice thermal conductivities of Melt+SPS sample and Melt+MS+SPS sample decrease by the scopes of 10.6%and 16.64%,respectively.As a result,the maximum dimensionless figure of merit ZT of 0.49 is obtained at 700 K for the Melt+MS+SPS sample.Compared with that of Melt+SPS sample,it is increased by 29%at the same temperature.