熔体旋甩法制备Sr_8Ga_(16)Ge_(30)笼合物的微结构及热电性能

The Microstructure and Thermoelectric Properties of Sr_8Ga_(16)Ge_(30) Clathrate Prepared by Melt Spinning

将熔体旋甩法(MS)用于制备Ⅰ-型Sr8Ga16Ge30笼合物,研究了MS对Sr8Ga16Ge30笼合物微结构及热电性能的影响。结果表明,MS得到的Sr8Ga16Ge30薄带自由面晶粒尺寸随冷却速率的增加而减小,接触面未有明显结晶现象。薄带经SPS烧结得到的致密块体结构中存在大量精细的层状结构。与熔融+SPS制备的试样相比,熔融+MS+SPS制备的Sr8Ga16Ge30试样的电导率变化不大,Seebeck系数增加,热导率显著降低,其中铜辊转速为4 000 r/min的Sr8Ga16Ge30试样的ZT值在800 K达到0.74,相对于熔融+SPS试样提高了45%。

Melt spinning（MS） technique was introduced to prepare type-I Sr8Ga16Ge30 clathrate,and the effects of MS on the microstructure and thermoelectric transport properties of Sr8Ga16Ge30 clathrate were investigated.The results showed that the free surface of ribbon obtained by MS consists of a large number of grains,and with the increase of cooling rate,the grain size reduced.However,there was no clear grain on the contact surface.After SPS the highly dense bulk material with lots of fine-layered structure was obtained.Compared with the sample prepared by melting combined with SPS（Melt＋SPS）,the electrical conductivity of the samples obtained by melting combined with MS and SPS（Melt＋MS＋SPS） varies slightly,the Seebeck coefficient increases,and the thermal conductivity decreased remarkably.As a result,the maximum dimensionless figure of merit ZT of 0.74 was obtained at 800 K for the MS4000 sample,which increased by 45% as to that of Melt＋SPS sample at the same temperature.