Quasi-hydrostatic Limit of LiF as a Pressure Transmitting Medium and Its Equation of States

Abstract

Quasihydrostatic limit of LiF as a pressure transmitting medium is investigated by synchrotron radiation x-ray diffraction combined with the diamond anvil cells technique up to 60 GPa at room temperature. The equation-ofstate parameters of LiF are determined to be 𝑉0 = 65.7(2) Å 3 , 𝐵0 = 58(3) GPa and 𝐵 ′ 0 = 4.9(2) in the silicon oil environment; 𝑉0 = 67.4(3) Å 3 , 𝐵0 = 51(3) GPa and 𝐵 ′ 0 = 4.7(2) without pressure transmitting medium. The full width at half maximum of LiF ( 111) peak increases with the increase of pressure in two independent experiments. The pressure distribution in the sample chamber is estimated by line-scanning x-ray diffraction measurements across the chamber's center, which presents as homogeneous with 𝑃max − 𝑃min of about 1 GPa below 40 GPa.

Molecular dynamics simulation of diffusion and viscosity of liquid lithium fluoride

“…As the coolant and carrier in the MSR [4,5], LiF improves the transport properties of the eutectic which composed by the thorium fluoride salt and carrier [6,7], enhances the energy efficiency of MSR [8], and reduces the possibility of incidents and makes a safer environment [9,10]. Moreover, LiF has potential applications as a pressure transmitting medium and a pressure calibrant in static measurements [11,12] and shock impression. So the studies of diffusion properties and flowability of LiF both are important for the practical significance.…”

Phase transition of intermetallic TbPt at high temperature and high pressure

“…After quenching, the diffraction peaks from the high-pressure phase remain at a high pressure (32.5 GPa), suggesting the high-pressure phase is temperature quenchable. As the quasihydrostatic pressure limit of LiF is 40 GPa and the consistency of the unit-cell parameters of LiF is calculated respectively from (1 1 1) and (2 0 0) diffraction lines, this indicates that quasi-hydrostatic stress in the sample was not larger after laser heating in this experiment [19].…”

Unusual suppression of tungsten 5d electron depletion in superhard tungsten tetraboride solid solution with chromium under compression

“…Because the pressure of 39 GPa is far above the hydrostatic limit of the pressure medium (silicon oil ∼10 GPa) and there is no interference peak from silicone oil [34], this result is unlikely caused by the deviation from hydrostaticity. Meanwhile, HP-XAFS results show a significant suppression of W5d electron depletion as observed in pure WB 4 at ∼21 GPa (figure 3(b)), which is much lower than the quasi-hydrostatic limit of LiF (∼40 GPa) [35]. In addition, the main reason to use solid LiF instead of the liquid or gas pressure medium for XAFS is to prevent the x-ray leakage through the sample that would be disastrous to the accuracy of the XAFS signals.…”