Mechanical and Electric Current Activation of Solid-Solid Reactions for the Synthesis of Fully Dense Advanced Materials

The so-called spark plasma sintering (SPS) is used in this work as a new time-saving sintering/synthesis method for the preparation of fully dense TiC/TiB2 ceramic composites and NbAl3 intermetallics. In particular, mechanically activated powders of starting materials are reacted and simultaneously consolidated once crossed by an electric pulsed current. Specifically, the effect of the most important parameters related to mechanical activation of starting reactants and synthesis/consolidation stage on process behavior and end-products characteristics is systematically investigated. The general result found in this study is that milling time and current level applied during the synthesis/densification strongly affect process dynamics, kinetics of synthesis process, as well as product relative density and crystallite sizes, which are reduced down to nanometric levels.