一套基于六面顶高压装置的静水压高频介电测试系统

 以一套6×14 400 kN六面顶高压装置和一台Agilent 4294A精密阻抗分析仪为主体，建立了一套静水压高频介电实时测试系统。通过固体传压介质预成型方法，解决了液体测试腔在固体传压介质中的密封以及包括4根微同轴电缆在内的多根测量导线引出密封边问题，将常压下通用的四同轴阻抗谱测试技术引入了高压研究。液体测试腔容积可达(Φ13×15) mm³，可同时容纳10 mm×10 mm样品、高频测试夹具、温度与压力传感器、加热装置，以及包括4根外径为1.6 mm、特性阻抗为50 Ω微同轴电缆在内的16根引线，进行室温至300 ℃、常压至3 GPa 静水压力、测试频率40 Hz~5 MHz范围材料的四线阻抗谱测量，实验误差小于3%。利用这套装置观察了室温下，BaTiO₃单晶在约2.6 GPa静水压力下的压致铁电-顺电相变。

A High Frequency Hydrostatic Pressure Dielectricity Measuring System Based on Cubic Anvil Apparatus

By a self-made system based on a cubic anvil high-pressure apparatus and an Agilent 4294A accurate impedance analyzer, real time high frequency dielectricity measurement under hydrostatic pressure is realized by the standard four-wire method widely used in ambient pressure dielectric research. The sealing of liquid cell in solid pressure-transmission medium and multi signal lines out through gaskets including four micro-coaxial cables is achieved by the pre-formation of pyrophyllite cube together with gaskets. The testing fixture, 10 mm×10 mm sample, pressure-temperature sensors and as many as 16 signal wires including 4 micro-coaxial cables with an outer diameters of 1.6 mm respectively can be contained simultaneously in a liquid testing cell with a volume of (Φ13×15) mm³. Four-wire impedance spectroscopy can be obtained by this system in a measurement range of room temperature to 300 ℃, ambient pressure to about 3 GPa hydrostatic pressure and testing frequency from 40 Hz to 5 MHz with an experiment error below 3%. The pressure induced ferroelectric-paraelectric phase transition of a BaTiO₃ single crystal is observed using this setting up.