High-Pressure Calibration: A Critical Review

Abstract

A critical review of experimental technique for measuring high pressures has been made. The broad coverage includes discussions relating to (a) the establishment of a primary pressure scale using the free-piston gage, (b) the selection and precise measurement of identifiable phase changes as fixed pressure points, and (c) the use of interpolation and extrapolation techniques such as resistance gages, equations of state, and optical changes. The emphasis is on static pressure measurements above 10 kbar, but shock measurements are also considered for completeness. The pressure values to be associated with the fixed points have been analyzed in detail. Temperature measurement in the high pressure environment is also reviewed. The accuracy with which pressures can be measured has been carefully considered; the maximum accuracies now obtainable are considered to be of the order of 0.02 percent at 8 kbar, 0.25 percent at 25 kbar, 2 percent at 50 kbar, and 4 percent at 100 kbar.

Oligomerization and carbonization of polycyclic aromatic hydrocarbons at high pressure and temperature

“…The room-temperature pressure calibration was carried out by monitoring the resistance changes in Bi [50] and Ba [51]. The pressure calibration at high temperature was performed using known phase transitions in SiO 2 (quartz-coesite) [52] and CaGeO 3 [53] at 1100°C.…”

Determination of the phase boundary of GaP using in situ high pressure and high-temperature X-ray diffraction

“…The equation of state of NaCl has been repeatedly investigated by previous studies [e.g. 21,[24][25][26][27][28][29][30][31]. In the future, a reliable equation of state for NaCl will be proposed, and the phase boundary between the semiconducting and the metallic phase determined in our study should be revised using the reliable equation of state.…”

High pressure neutron and X-ray diffraction at low temperatures

“…It is important that the calibrant is of high crystal symmetry, introducing only a few well-defined parasitic peaks to the diffraction pattern. A useful critical review of these methods may be found in the work of Decker et al [69] and Klotz [16].…”