Surface Tension as a Motivation for Sintering

Abstract

The sintering together of powder particles into a dense solid mass at temperatures below the melting point of the particles is a process whose rate and end result are known to be influenced by many factors, e.g., particle size, distribution of particle sizes, compacting pressure, temperature of sintering, surrounding atmosphere, gas dissolved in the particles, etc. Because of the many factors involved, it is difficult to draw from practical metallurgical results any reliable conclusions regarding the detailed laws governing the processes occurring. Recently, however, interest has been growing in attempts to isolate the physical processes likely to be important and to study them in experiments designed for unambiguous interpretation. Such experiments have a twofold interest, in that they not only provide clues toward the elucidation of more complicated metallurgical phenomena but also throw light on some fundamental fields of solid-state physics. This chapter undertakes to provide a broad and logically precise formulation of certain physical laws which underly the interpretation of some of the simplest experiments of this type.