High Pressure Gas Apparatus for Measuring Ultrasound Velocity in Matters up to 4 GPa

Abstract

A piston-cylinder apparatus using gases, which could produce hydrostatic pressures of up to 4 GPa and temperatures of up to 800°C is described. A high-pressure tapered cylinder made of 350 maraging steel was 262 mm long and had a 19 mm inside diameter and a working space of 100 mm in length at 4 GPa. The support ring was made of 300 maraging steel and was approximately 180 mm thick and 420 mm in outside diameter. For measurements of both the pressures and temperatures, a manganin gauge and a thermocouple were placed inside the tapered cylinder. No difficulty was encountered with any of these components at pressures of up to 3.5 GPa. This apparatus could be used almost indefinitely, since neither a considerable change of the bore nor surface cracks in the tapered cylinder had been found thus far.