Initiation of self-propagating high-temperature synthesis by a pulsed microwave discharge

It is shown that a metal plasma with a temperature of 10 kK arises on the surface of a metal-insulator powder subjected to a 0.3-to 1.0-ms-long microwave pulse. The pulse triggers an exothermal chemical reaction in the Ti-B or Al-Fe₂O₃ powder mixture, the delay between the end of the pulse and inflammation of the mixture reaching 10–20 ms. The microwave irradiation results in a high local energy deposition causing evaporation and rapid mixing of the reactants. This distinguishes the early stage of the reaction triggered by microwave radiation from the reaction in the case of conventional thermal initiation.