n型Bi_2Te_3块体材料的放电等离子烧结及其性能研究

Fabrication and Properties of n-type Bismuth Telluride Bulk Materials by Spark Plasma Sintering

采用放电等离子烧结法(SPS)在400℃、420℃、440℃的烧结温度下制备了n型Bi2Te3块体材料,利用X射线衍射对块体材料进行了物相分析,在300～500 K的温度范围内分别测量了块体材料的塞贝克系数α、电导率σ以及热导率κ,利用MSP(Modified Small Punch)小样品试验法对块体材料进行了力学性能分析。结果表明:400℃烧结材料的热电性能优值ZT具有最大值,约为0.79;块体材料在440℃时具有最大的MSP断裂强度,约为119.5MPa,表明了MSP试验法是评价小尺寸陶瓷材料力学性能方便、可靠的有效方法。

n-type Bi2Te3 thermoelectric materials were sintering method at 400 ℃, 420℃ and 440℃. The phase structure characterization of the samples were analyzed by X-ray diffraction pattern （XRD）. The thermoelectric properties, including seebeck coefficient （α）, electrical conductivity （σ） and thermal conductivity （κ） were measured in the temperature range of 300-500 K. The MSP （Modified Small Punch） strength of n-type Bi2Te3 thermoelectric materials was discussed in detail. It was found that the maximum ZT value is about 0.79 of the sample sintered at 400℃, and the maximum MSP strength is about 119.5 MPa of the sample sintered at 440℃. It showed that MSP tests are reliable, convenient and efficient evaluation methods for ceramic materials by using quite small specimens.