【摘要】 采用新颖的熔体旋甩(MS)结合放电等离子烧结(SPS)技术制备了单相Zn掺杂的Ⅰ-型Ba8Ga12Zn2Ge32笼合物,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,MS得到的薄带自由面主要由300nm—1μm的小立方体单晶组成,薄带经SPS烧结后得到了具有大量层状精细结构的致密块体.与熔融+SPS工艺制备的试样相比,熔融+MS+SPS制备的Ba8Ga12Zn2Ge32笼合物室温载流子浓度增加而迁移率降低,在测试温度范围内,试样的电导率略有下降,Seebeck系数增加,热导率和晶格热导率显著降低,900K时其晶格热导率从1.06W/mK降低至0.42W/mK.熔融+MS+SPS制备的Ba8Ga12Zn2Ge32笼合物试样在900K时其最大ZT值达到0.90,与熔融+SPS试样相比提高了75%.更多还原

【Abstract】 The single-phase Zn-doped type-I Ba₈Ga 12 Zn₂Ge 32 clathrates have been prepared by a 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—1.0μm,and after SPS a highly dense bulk material with lots of fine-layered structure has been obtained.Compared with the bulk Ba₈Ga 12 Zn₂Ge 32 material prepared by melting method combined with SPS（MM+SPS sample）,the bulk Ba₈Ga 12 Zn₂Ge 32 material obtained by melting method combined with MS and SPS（MM+MS+SPS sample） has higher carrier concentration and lower carrier mobility at room temperature.Furthermore,the MS process leads to a slight decrease of electrical conductivity,somewhat increase of Seebeck coefficient,as a well as a remarkable decrease of lattice thermal conductivity for bulk Ba₈Ga 12 Zn₂Ge 32 clathrates in the testing temperature range of 300—900 K.At 900 K,the lattice thermal conductivities of MM+SPS sample and MM+MS+SPS sample are 1.06 and 0.42 W/mK respectively.As a result,the maximum dimensionless figure of merit ZT of 0.90 is obtained at 900 K for the MM+MS+SPS sample.Compared with that of MM+SPS sample,it increases by 75% at the same temperature.更多还原