Refractive index of MgAl2O4 transparent ceramic under quasi-isentropic compression loading

Abstract

ABSTRACT The indirect method of obtaining in situ particle velocity of sample, under dynamic high-pressure loading experiments, generates an error due to the influence of rarefaction wave from the sample-window interface. Using the spinel as a window is an attractive method to reduce the error due to the total impedance matching of sample and window in the loading experiments of the spinel. To explore the possibility of the spinel as a window, ramp wave compression experiments were conducted to determine the refractive index of loading longitudinal stress range below 15.9 GPa. The result showed smooth particle velocity curve and linear relationship between refractive index and density. The effect of temperature on refractive index can be negligible, proved by analyzing the effect of temperature on polarizability. It is indicated that the spinel can be used as a window for loading experiments of the spinel and similar impedance materials.