Synthesis of isomorphous copper-nickel and immiscible copper-niobium materials by shock-compression

Shock-induced reaction synthesis (SRS) refers to the process of in-situ induction of chemical reaction between two (or more) elemental powders by application of high pressures and temperatures involved in shock-compression. This mode of initiating chemical reactions by shock-compression has become a subject of increasing interest over the last ten years. The field is thought to hold promise for future technological developments, though a number of scientific questions are required to be understood prior to application of the process. Research on SRS has primarily focused on the experimental synthesis of materials, with the aim towards development of an understanding of the process mechanisms. While several organic polymers and inorganic materials have ben synthesized by SRS, considerable attention has been paid to the processing of intermetallic compounds by this method. Aluminides and silicides of nickel, titanium and niobium and zinc ferrite are examples of intermetallics that have been prepared from elemental powders by SRS processing. This paper reports that the experimental studies have also indicated that shock conditions and powder characteristics are key to SRS, though a fundamental understanding of the process is lacking. This is because a large number of changes including visco-plastic deformation, cleaning of powder surfaces leading to enhanced reactivity, solid state diffusion and localized or bulk melting at enhanced rates, and formation and crystallization of end products are possible within the microsecond duration of the shock-front