Microwave assisted sintering of green metal parts

Microwave processing has gained worldwide acceptance as a novel method for heating and sintering a variety of materials, as it offers specific advantages in terms of speed, energy efficiency, process simplicity, finer microstructures, and lower environmental hazards. Microwave assisted post-treatment of green metal parts (AISI 420 metal powder with 2-3wt% polymeric binder) proved to be a new method, suitable for near-net-shape and net-shape manufacturing. Green parts exposed to high intensity microwave fields, using either single mode or multimode microwave applicators operating at 2.45 GHz ISM frequency, were investigated in terms of densification behaviour, microstructure and joining micromechanism. The results, in terms of microstructure and shape retention are comparable to the conventional heating ones, reported in literature, but they have been obtained in much shorter time. (C) 2007 Elsevier B.V. All rights reserved.