Atlas manual hydraulic press 15t

Powder compaction was performed via
cold uniaxial pressing resulting in a regular disk-shaped specimen.
A defined mass of powder (m = 150 ± 10 mg) was
transferred into the cavity (d = 13 mm) of a compaction
tool (FTIR Pellet Dies, Specac) and uniaxially compressed with a hydraulic
press (Atlas manual hydraulic press 15T, Specac) under an applied
pressure between p = 1 MPa and 74 MPa that was dwelled for 1 min to
obtain green compacts in a controlled and reproducible way. To minimize
the amount of water adsorption, powder transfer and compaction was
performed inside glovebags filled with Ar at room temperature.

The measurement set-up was derived from Gabhi et al. [51 (link)] and is sketched in Figure 1a for fillers and Figure 1b for composites. The instrument was composed of two solid copper cylinders, 30 mm in diameter and 5 cm in length, encapsulated in a hollow Plexiglas cylinder with a nominal inner diameter of 30 mm in the case of filler electrical characterization. In this configuration, the inner diameter was slightly higher so that it was possible to force the copper rods inside the Plexiglas cavity and the upper rod could slide inside the cylinder during the measurement. This arrangement created an internal chamber between the two cylinders, where the carbon powder could be inserted. In the case of composites, the Plexiglas cylinder was removed and the sample was positioned between the aligned copper cylinders. The electrical resistance of the powders or composites was measured at increasing loads (up to 1500 bar) applied by a hydraulic press (Specac Atlas Manual Hydraulic Press 15T). Electrically insulating sheets were placed between the conductive cylinders and the load surfaces in order to ensure that the electrical signal passed through the sample. The resistance of the carbon fillers was measured using an Agilent 34401A multimeter.

Compaction
of FSP-grown nanocrystals was performed by transferring a defined
mass of the powder (m = 150 ± 10 mg) into the
cavity (d = 13 mm) of a compaction tool (FTIR Pellet
Dies, Specac) followed by uniaxial compression (p = 74 MPa, t = 1 min) with a hydraulic press (Atlas
Manual Hydraulic Press 15T, Specac). Disk-shaped green bodies are
reproducibly obtained in this way, whereby porosities Φ of green and sintered compacts can be calculated geometrically through
the weight and volume of the pellets via eq 1
To account for the volume
fraction
of admixed metal ions in the theoretical density values of Me_xMg_1–xO
systems, we applied the rule of mixture (see the Supporting Information).
Pressureless sintering
of the green bodies was performed within
a horizontally operated high-temperature ceramic tube furnace (Nabertherm
RHTH80-300/16). Disk-shaped green bodies were sandwiched between alumina
plates to guarantee smooth ceramic surfaces after sintering and placed
on an alumina crucible in the middle of the tube furnace. Synthesis-related
carbonaceous species become eliminated via application of a continuous
flow of molecular oxygen [Q(O₂) = 50 mL
min^–1] during the sintering protocol. Specimens
were heated with 5 K min^–1 to the final temperature
of 1373 K, dwelled at this temperature for 2.5 h, and then the furnace
cooled to room temperature.

In a recent paper, the preparation of MFI-type zeolite pellets was described [8 (link)]. The pelletization apparatus is divided into two parts: a manual hydraulic press (Atlas 15T Manual Hydraulic Press, Specac) and a pellet die where the powder is incorporated. The zeolite pellets were prepared from a mixture of binder, 1:4 zeolites (FAU, BEA, LTA and MFI-types) to water. First, distilled water was mixed with a certain amount of binder (5 wt % of the pellet for optimized conditions). This amount of water was optimized: if too much water is added, the mixtures cannot be pelletized (the mixture is liquid). On the other hand, with too little binder, cracks appear after the ejection of pellets. Then, zeolite is added. Water improves the diffusion of binder in zeolite powder and allows the formation of a MC or Na₂SiO₃ gel which acts as glue that holds particles together. The mixture was stirred and put in the pellet die for pelletization. A definite compression load was applied during 5 min in order to form a pellet. The pellets were finally dried at 70 °C during 24 h.

Cylindrical, flat, 13 mm diameter, 250 mg pellets were produced using an Atlas 15 T Manual Hydraulic Press (Specac Ltd, Orpington, UK). Three tonnes were applied for a duration of 30 s. Two pellets were produced for each batch; one from the powder ‘as received’ and one from the corresponding ball milled sample.