Sinterizzazione a microonde di polveri sferiche da lavorazioni industriali

Microwave sintering in air of spherical powders generated during EDWC (Electrical Discharge Wire Cutting) has been studied. The main objective of the investigations is to determine if, with respect to conventional heating systems, microwave assisted heating can produce variations of the thermo-chemistry and kinetic of the chemical-physical phenomena occurring at the solid state during sintering.The powders used are made mainly by Cu/Zn and Fe/Cr/Ni micro spheres. The microwave applicator is a single mode TE10n , fed by a magnetron operating at 2.45 GHz. Microwave sintering resulted enhanced with respect to conventional heating. As a matter of fact, the highest densification occurred at temperature 100-200°C lower than conventional furnace. Moreover, the microstructure of the microwave sintered samples is completely different, presenting lower oxidation and retention of spherical metallic inclusions. These phenomena can be explained considering that the electromagnetic field is concentrated in proximity of the regions of necking.