(a) Ring heater assembly. (b) Top view of the ring heater. Flexible graphite foils on each side are pressed between the ring-shaped heaters to supply electric current from Mo rod to the graphite heaters. (c) Photomicrograph of ring heater assembly. Two type-R thermocouples (TC) are cemented onto the pavilion of the diamond to measure temperature.
(a) Cross section of resistively heated diamond-anvil cell assembly. The DAC is modified from a standard symmetric cell, made of Vascomax 350 (Princeton Symmetric DAC). (b) Overview of the cell design. Two 5 mm wide, 7 mm deep grooves are cut by EDM on the piston side to allow the Mo rods to be inserted. Also note that the cut shown on the right-hand side of the DAC cylinder is also produced by EDM but is not necessary for this design. A cylindrical alumina sleeve between the DAC and the membrane can is also used, however, not required to thermally insulate the DAC.
Temperature as function of power at ambient pressure in external resistively heated DAC. Diamond culet temperatures are measured by a type-R thermocouple, while the diamond table and WC seats are measured by a type-K thermocouple. The temperatures are monitored throughout and are reported here only after reaching steady state. Note the strong linear relationship between temperature and power. Uncertainties in temperature are ±10 K.
Water ice VII melting curve as function of pressure. Four melting points are plotted in comparison with melting curves of previous studies 26,29,38,39 using external resistively-heated DACs.
X-ray diffraction patterns of a sample of Au and MgO before (thin line) and during heating (thick line) at high pressures. The hkl's of both Au and MgO are noted.
Pressure-temperature path of Au/MgO sample during heating. At the highest temperature of 1300 K, a pressure of ∼51 GPa was reached and held constant for 1 h. The dashed line through the data points is a guide for the eye.
Article metrics loading...
Full text loading...