Ponderomotive effects during contact formation in microwave sintering

An assessment of the ponderomotive effect contributions to the kinetics of single contact growth during sintering is carried out. A considerable free surface electromigration during microwave sintering in a polarized electromagnetic field is determined at inter-particle interfaces. It is shown that the electromigration flux reaches its maximum near the inter-particle contact edge and it is equivalent to the compressive stress acting on the contact between particles. The compressive stress is proportional to the intensity of the electric field at the inter-particle neck and inversely proportional to the ratio of the grain boundary and surface diffusivities. The electromigration matter transport can substantially accelerate the shrinkage rate during microwave sintering in comparison with conventional sintering.