The sample is sealed within a pressure medium and reacted under conditions reaching up to 2.5 GPa (25,000 atmospheres) and 1,600°C. By sealing the sample to create a completely closed system, it is possible to synthesize materials that cannot be produced at ambient (atmospheric) pressure; this is achieved by preventing the evaporation of elements and by exploiting phenomena such as differences in compressibility between cations and anions or transitions to high-density phases.

The Keramax heater enables a maximum operating temperature of 1800°C. By evacuating the furnace tube using a rotary pump, firing can be performed in inert gas (argon, nitrogen), oxygen, or vacuum atmospheres.

The sample is sealed within a quartz glass tube at a very low pressure of 10⁻⁵ Torr (where 1 atm is 760 Torr) and reacted under conditions that prevent the incorporation of atmospheric nitrogen, oxygen, and the like during synthesis.

While combining this apparatus with an electric furnace allows for relatively easy synthesis under high-vacuum conditions, it is unsuitable for synthesis requiring high temperatures (1100°C or higher) that would cause the quartz glass to melt.

The interior of the unit is purged and sealed with high-purity inert gas (Ar), enabling operations to be performed via gloves. Thanks to an integrated gas circulation and purification system, a high-purity inert gas atmosphere—characterized by low oxygen and moisture levels—can be maintained over an extended period.

A container (pot mill) holding the sample and hard grinding media, such as zirconia balls, is subjected to both rotational and orbital motion. This generates greater grinding energy than a conventional ball mill, enabling the sample to be pulverized into extremely fine particles.

This method is widely used in mechanical alloying to produce non-equilibrium materials—such as metastable phases—that cannot be obtained under standard thermal equilibrium conditions.