PbTe的高温高压合成

PbTe SYNTHESES BY HIGH-PRESSURE AND HIGH-TEMPERATURE APPROACH

以高温高压为手段 ,在 4～ 5GPa压力和 70 0～ 1 2 0 0K温度条件下 ,成功地合成出了PbTe。对合成样品进行了X射线测试分析 ,结果表明 ,合成的PbTe样品是具有NaCl结构的多晶 ,而PbTe的取向随着合成压力的升高发生变化。扫描电镜分析结果显示 :高压合成的PbTe样品 ,其晶粒有了明显的取向 ;电阻率比常压样品低 1～ 2个数量级 ,并随合成压力的升高而降低 ;热导率也同时低于常压合成的PbTe样品。以上结果说明 ,高压合成方法是改善材料性能的重要手段。

Lead telluride was successfully synthesized by a high-pressure and high-temperature(HPHT) method. XRD results show that the samples are polycrystalline with rock salt structure. The orientation of PbTe samples is varying with the increasing synthesis pressure. Scanning electric microscope (SEM) results show that the synthesized PbTe samples possess high orientation. The electrical resistivity of PbTe samples is about 1-2 magnitudes lower than those of the samples sintered at ambient pressure, and decrease with the increase of the synthesis pressure. The thermal conductivities of the PbTe samples synthesized by HPHT are lower than those of the samples fabricated at ambient pressure. These results indicate that thermoelectric properties of PbTe samples can be improved by high-pressure and high-temperature approach.