Role of interfaces in sintering

Abstract

The paper reviews experimental and theoretical results emphasizing the role of interfaces in sintering processes. In the absence of chemical reactions, the excess energy of the solid/pore interface provides the driving force for material transport. Grain boundaries and surfaces are the most active sinks and sources, as well as important transport paths for the directed flow, of vacancies. While the understanding of idealized sintering models is well advanced, the complex processes (and their interaction) typical of real systems are still in the stage of phenomenological investigation. Present interest is focused on the influence of chemical reactions (especially homogenization) and on the effectiveness of grain boundaries as vacancy sinks and as dislocation sources under the action of capillary forces. Some corollaries for the sintering behaviour of technical powders, including the effects of dopants, are discussed.