The Role of Preceding Parallel Chemical Reactions and Reactive Nanoclusters in the Processes of Phase Transformations of Intermetallic Compounds

Resumo

Using the chemical, electrochemical, and X-ray phase analysis, it has been shown that intermetallic compounds in Zn–Sb, Cd–Sb, Mg–Sb, and Al–Sb systems dissolve mainly with metal ionization, partial ionization of antimony, and parallel processes such as “intermetallic compound–Sb” phase rearrangement and reverse reduction of the Sb³⁺ cations. It is postulated that the phase transformation process proceeds with the formation of a defective crystal lattice and appearance of reactive nanoclusters that interact to produce nuclei of a new phase and then a crystal structure. This process proceeds on the background of a partial uniform dissolution of the studied intermetallic compounds with reverse electrochemical reduction of Sb(III) cations in successive independent processes, as well as the parallel formation of the Sb-based few-atomic reactive clusters and further polyatomic nuclei of a similar phase. Chemical and electrochemical processes occur independently, but their relative rate depends on the magnitude of the potential determined by the level of cathodic and anodic polarization.