Problems in mechanochemistry and prospects for its development

Probing the tribochemical degradation of hydrogenated amorphous carbon using mechanically stimulated gas emission spectroscopy

“…Using molecular dynamic (MD) simulation of a-C:H Schall et al [61] determined that under severe sliding with normal stress of 7.6 GPa and sliding velocity of 90.2 m s À1 the temperature increase in a 2.5 Å thick section containing interface was only 282 ± 146 K. Ma et al [62] carried out MD simulation under even severer sliding conditions and proofed that the effect of the hot spots on hydrogen depletion and degradation of a-C:H could be neglected. These conclusions are in line with the basic principles of mechanochemistry pointing that neither the total heat evolution nor local hot spots have significant influence on the mechanochemical processes [63,64]. Another argument against the hot spots is their short life, which typically does not exceed 10 À12 to 10 À11 s due to decay via phonon excitation [14].…”

Mechanochemical activation of aluminum: 1. Joint grinding of aluminum and graphite

“…At the initial part of the curve, the specific surface area increases linearly and reaches the maximum value (about 300 m 2 /g) at the dose equal to approximately 10 kJ/g. In the experiments with graphite, the work of surface formation is equal to 33 J/m 2 that is coincident with the published data [15]. The S values for graphite (right scale) and Al-C mixture (left scale) differ fourfold, and the points corresponding to measured S values fit the same straight line up to a dose of 6 kJ/g within the limits of experimental error.…”

Structural changes in silver iodide upon mechanochemical treatment

“…Changes that can result in restruc turing can occur in solid bodies upon mechanical treatment [4]. Ina ddition, both an increase in the sur face area and the creation of defects in the crystal lat tice give rise to elevated chemical activity [2,3].…”