Information on the mechanism of mechanochemical reaction from detailed studies of the reaction kinetics

Synthesis of Pure NiTiSn by Mechanical Alloying: An Investigation of the Optimal Experimental Conditions Supported by First Principles Calculations

“…Below 500 rpm, NiTiSn does not form during the reaction and a multiphasic material mostly composed of binary Ni-Sn compounds is obtained. This is in agreement with a minimal impact energy needed to initiate the chemical changes evidenced in kinetic measurements [22] also showing that the number of collisions can be used, instead of the reaction time, as a kinetic parameter. An increase of the reaction time has no visible impact on the nature of the formed phases, and in no case, NiTiSn was observed even after long reactions extended up to 43 h.…”

“…It can be asserted that, below this speed limit, the minimal impact energy needed to initiate a chemical change into the ternary alloy is not reached [22] and that the energy which is provided to the sample only leads to the formation of binary compounds. On the other hand, a too high energy is not favorable to form NiTiSn during the longest reactions.…”

“…Trials to model this complex relation remain scarce and limited to a single ball problem [20,21]. A recent work describes a stochastic model to investigate the kinetics of gradual mechanical reactions in simple conditions (shaker mill and single-ball), which is suitable to obtain helpful and valuable microscopic parameters [22].Resulting materials are most of the time metastable and expected to transform in thermodynamically stable products. Then subsequent annealing may be needed to achieve the alloying process [23].…”

“…Trials to model this complex relation remain scarce and limited to a single ball problem [20,21]. A recent work describes a stochastic model to investigate the kinetics of gradual mechanical reactions in simple conditions (shaker mill and single-ball), which is suitable to obtain helpful and valuable microscopic parameters [22].…”

Preface

“…The next six papers cover different aspects related to theoretical and experimental studies, which might help in the quest for understanding the particularities of mechanochemical processes; Delogu and Takacs analyze the possibility of inferring the mechanism of mechanochemical reactions by using systematic kinetic studies, carried out under well-defined and simple mechanical conditions [2]. Javanbakht and Levitas apply a phase field approach (PFA) to describe strain-induced phase nucleation and growth, under compression and shear forces [3], whereas Suryanarayana's paper describes some specific features of mechanical alloying for the synthesis of metastable phases, when compared to rapid solidification processing, which is another well-known nonequilibrium processing method [4].…”