Mechanochemical synthesis of intermetallic compounds

Abstract

The current state of studies on the mechanochemical synthesis of binary metallic systems is considered. It is shown that this method is suitable for the preparation of intermetallic compounds and solid solutions in concentration limits of equilibrium diagrams of many binary systems. The mechanochemical approach is demonstrated to exhibit the most promise for preparing intermetallic compounds in systems characterised by large differences in the melting points and in the densities of the initial components as well as phases with nanometer grain sizes and metastable phases. The major factors, which influence the concentration limits of existence of non-equilibrium solid solutions prepared by the mechanochemical method, are revealed. Using numerous examples, it is demonstrated that the formation of solid solutions may involve several stages. At the first stage, nanosized layered composite structures are formed with simultaneous dispersion of the initial components (the formation of a large contact area). The second stage involves the synthesis of intermetallic compounds in nanosized layered composites. At the third step, the intermetallic compounds are dissolved in a metal solvent to give a solid solution. The bibliography includes 397 references.