Cylindrical High Temperature, High Pressure Apparatus

Abstract

A description is given of a cylinderical high pressure apparatus which can be used in the pressure range of up to 100 000 atm and for temperatures of up to 1500°C. The high pressures are generated by means of a pressurized rubber tire acting on three identical segments. Each segment is provided, near the center of the apparatus, with a tungsten carbide cylinder. The high pressures are transmitted to the surfaces of a pyrophyllite sample holder when the three tungsten carbide cylinders with parallel axes are brought together. The high pressure calibration was based on the observed linear relationship between the water pressure in the tire and the transition points of, respectively, bismuth, thallium, and barium. It turns out that the pressure is practically independent of the axial coordinate. A thin-walled graphite cylinder with a wall thickness of 0.1 mm, used for heating purposes, is placed along the axis of the sample holder. This graphite cylinder is insulated from the sample by means of boron nitride, and there was no difficulty in making separate contacts for the furnace and the sample. Temperature indication during the operation of the apparatus was obtained by measuring the resistance of p-type germanium. In the testing of this apparatus at higher temperatures, up to 1500°C, synthetic diamonds of about 0.3 mm were produced.