The cell. (1) Ti–Zr alloy sample compartment; (2) 150 ml expansion vessel (Swagelok®, 316 L-HDF4–150); (3) 150 ml fluid reservoir (Swagelok®, 316 L-HDF4-150); (4) two tabular heaters (Helios®, 690 W total); (5)–(7) -type thermocouples, measuring the temperatures at (5) the center of the fluid reservoir, (6) the top of the sample compartment, and (7) near the pressure relief valve; (8) pressure gauge (Swagelok®, 0–10 MPa); (9) pressure relief valve (Swagelok®, 5–10 MPa, R3A-C); (10) condensation tube (Swagelok®, in. tubing); (11) top ball valve (Swagelok®, SS-4SKPS4); (12) bottom fill/drain ball valve (Swagelok®, SS-33PS4); (13) power leads of the heaters, connecting to a temperature controller (Shinko® JCR-33A-S/M); (14) enlarged view of the sample tube constructed from 316-type stainless steel mesh (Locker Group®, aperture size ). The components are connected by Swagelok® in. tubing, tees, and crosses, and nuts. The support system, the aluminum/polycarbonate shield, and the other ancillary components are shown in Fig. 2.
Setup of the hydrothermal cell on Wombat, the high intensity powder diffractometer in ANSTO. (1) Aluminum shield; (2) front transparent polycarbonate shield; (3) threaded support rods; (4) aluminum foil wrapped ceramic insulation block; (5) Pyrex® glass spill tray; (6) surveillance camera; (7) support clamps; (8) support base; (9) neutron beam guide; (10) sample stage; (11) neutron beam stop; (12) collimator; (13) detector; (14) temperature-recording unit (LakeShore®, Model 340).
In situ neutron diffraction patterns of the transformation from leucite to analcime . (a) Two-theta range from 40° to 83°, showing the progressive phase transformation; the stainless steel phase has constant peak intensities, serving as an excellent internal standard; the zero-scattering Ti–Zr alloy sample compartment has no diffraction peaks, giving an excellent flat background. (b) Two-theta range from 77° to 83°, highlighting the progressive increase of analcime peaks and decrease of leucite peaks. peaks, peaks, peaks where leucite is the dominant phase, peaks where analcime is the dominant phase, steel peaks.
(a) Mass fractions of the three involved phases as a function of reaction time during the transformation from leucite to analcime . Note that the total mass of the sample changed from 1.25 g at the beginning of the reaction to 0.92 g at the end because of the loss of small particles from the mesh tube; however, the mass of the stainless steel mesh tube remained constant at 0.57 g, so the mass fraction of (Fe,Ni) slightly increased during the process, serving as an excellent internal standard for quantification. (b) An Avrami plot yields the rate constant and the time component as shown in the plot.
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