Simultaneous velocity and attenuation measurements applicable to various solids at high pressures and temperatures up to 1200 °C

Abstract

A technique has been developed for measuring acoustic velocity and attenuation simultaneously at high pressures and temperatures. By observing both the direct (first) and reflected (second) echoes, the travel time and wave attenuation only within the sample can be determined accurately at high temperatures, regardless of the buffer rod geometry. The high acoustic impedance of platinum is suitable as a buffer rod for observing both the direct and reflected waves in various samples of ceramics, minerals, glasses and light metals. By using platinum rods, we determined compressional wave velocity and attenuation in fused silica at temperatures up to ∼1200 °C and a static pressure of 1 GPa. Measured velocities were consistent with the values reported earlier. In general, the acoustic impedance of platinum is much higher than that of ceramics, minerals, rocks, glasses and light metals. Therefore, the present method should be applicable to velocity and attenuation measurements for various solids at high pressures and temperatures.