High-Pressure Apparatus Using Pressure Generated by Restraining Thermal Expansion

机械式高压装置通常用于研究和生产。然而，这种类型的设备需要大型液压机，并且尺寸变大且结构复杂。此外，摩擦力和压力泄漏的反作用是一个问题。使用通过抑制热膨胀产生的压力的装置不伴随摩擦力和压力泄漏。作者提出了这种装置，它由一个导体球和一个硬绝缘圆筒组成。在该设备中，只有内部球通过感应加热。然而，该装置需要大量的工作来进行设置和压力测量，因为它需要使压力容器绝缘。此外，作为压力源的球体需要具有良好的导电性，本研究设计了一种新型的基于热能的高压装置。在该装置中，压力容器由钢制成，并且在压力室中插入炉。通过抑制插入压力室中的NaCl和LiF的热膨胀来产生高压。建立了计算装置内压力的方法。利用计算方法对装置进行了详细的设计，并进行了试制，计算结果如下.设计了一种温度分布均匀的加热炉.该装置适合于SiC炉.当用NaCl和LiF作压力源时，在1000 ℃下分别产生了2.4和4.2GPa的高压，而且用Pb的熔点与压力的关系测量证实，该装置在400 ℃下产生了1GPa的高压。

A mechanical type of high-pressure apparatus has usually been used for studies and productions. However, this type of apparatus requires a large hydraulic press and becomes large in size and complicated in structure. Furthermore, countermoves for frictional force and pressure leakage are the problem.An apparatus using pressure generated by restraining thermal expansion is not accompanied with frictional force and pressure leakage. The author has proposed this type of apparatus which consists of a conductor ball surrounded by a hard insulating cylinder. In the apparatus only an inside ball is heated by induction. However, the apparatus requires much work for set-up and pressure measurements, because it is necessary to make the pressure vessel of insulator. Furthermore, the ball used as pressure source requires good conductivity.In this study, a new type of high-pressure apparatus based on thermal energy was devised. In this apparatus, the pressure vessel was made of steel and a furnace was inserted in the pressure chamber. High pressure was generated by restraining thermal expansion of NaCl and LiF inserted in the pressure chamber. A method of calculating pressures generated in the apparatus was established. The apparatus was designed in detail using the calculating method and it was built as a trial.Results obtained from the calculations are as follows.1. A furnace with homogeneous temperature distribution was designed.2. A furnace which consists of SiC is suitable for the apparatus.3. When NaCl and LiF are used as pressure source, high pressures of 2.4 and 4.2 GPa are generated at 1000 ^ﾟC respectively.Furthermore, it was confirmed by the measurements using the pressure dependence of melting point of Pb that the apparatus produces a high pressure of 1GPa at 400^ﾟC.