New horizon in mechanochemistry-high-temperature, high-pressure mechanical synthesis in a planetary ball mill-with magnesium hydride synthesis as an example

A new route of materials synthesis, namely, high-temperature, high-pressure reactive planetary ball milling (HTPRM), is presented. HTPRM allows for the mechanosynthesis of materials at fully controlled temperatures of up to 450 degrees C and pressures of up to 100 bar of hydrogen. As an example of this application, a successful synthesis of magnesium hydride is presented. The synthesis was performed at controlled temperatures (room temperature (RT), 100, 150, 200, 250, 300, and 325 degrees C) while milling in a planetary ball mill under hydrogen pressure (> 50 bar). Very mild milling conditions (250 rpm) were applied for a total milling time of 2 h, and a milling vial with a relatively small diameter (phi = 53 mm, V = similar to 0.06 dm(3)) was used. The effect of different temperatures on the synthesis kinetics and outcome were examined. The particle morphology, phase composition, reaction yield, and particle size were measured and analysed by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry (DSC) techniques. The obtained results showed that increasing the temperature of the process significantly improved the reaction rate, which suggested the great potential of this technique for the mechanochemical synthesis of materials. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.

Automated summary

A new route of materials synthesis, high-temperature, high-pressure reactive planetary ball milling (HTPRM), is introduced in this study. It allows for the controlled mechanosynthesis of materials at temperatures up to 450 degrees C and pressures up to 100 bar of hydrogen. The successful synthesis of magnesium hydride is presented as an example of the application, demonstrating the great potential of this technique for the mechanochemical synthesis of materials.