Early treatments of sintering realized that grain size was an important metric for predicting the sintering rate. As well, properties of sintered materials pivot around grain size. With nanoscale powders there is a greater demand for coarsening control during sintering. The conditions needed to induce sintering depend on the material and a host of processing variables. During sintering there is significant microstructure coarsening, evident as grain growth and pore growth via interlaced events including changes in porosity, pore size, grain coordination, interface wetting, and grain boundary area. After an initial transient, sintering converges to a self-similar grain shape and grain size distribution. For sintering microstructures microstructure evidences both complexity (multiple interfaces with changing compositions and morphology) and simplicity (only a few parameters genuinely dictate coarsening). These relations are summarized here to show how grain coarsening can be treated during sintering.
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