Estimation of uniaxial stress component in NaCl samples compressed in a tungsten carbide anvil high-pressure x-ray apparatus

The uniaxial stress component (USC) in NaCl samples compressed in a tungsten carbide opposed anvil high-pressure x-ray apparatus has been determined to 10 GPa by a method proposed earlier by Singh and Kennedy. In the pressure range 1–10 GPa, the pressure dependence of the lower estimates of USC can be expressed by the relation t (p) =0.24(±0.04)+0.11(±0.005) p, where t (p) is the USC at a pressure p, t (p) and p being expressed in the units of gigaPascals (GPa). These results have been used to estimate the difference, ΔP, between the pressures calculated from the hydrostatic component of strain and the strain averaged for the first six strong reflections of NaCl. ΔP is found to increase linearly from ∼0.1 GPa at 1 GPa to ∼0.4 GPa at 10 GPa.