Sintering

The results of experimental and theoretical investigations of the sintering process in crystalline solids are reviewed in a primarily pedagogical manner. Emphasis is placed on elucidating the origin of the driving force for the process and the mass flow mechanisms controlling sintering so as to establish a logical basis for understanding the effects of various parameters on densification kinetics. In this respect, the effects of the aggregation of powder particles in the unsintered compact, grain growth during sintering, and reducing the average particle size in the starting powder, are discussed in detail. The essential features of theoretical models of initial, intermediate, and final stage sintering are outlined; and the degree to which these models are successful in predicting the course of the process is discussed. (Author)