Pore Growth during Initial-Stage Sintering

A quantitative model for pore growth during initial‐stage sintering is proposed. During initial‐stage sintering, neck formation leads to surface rounding of the pores, thereby causing a decrease in the surface area of the system. The decrease in surface area, without a concomitant decrease in pore volume, leads to a spurious increase in pore size, as calculated by the gas adsorption technique. Geometrical calculations predict a final pore size that is a function of the initial (green) density of the compact. For the 62% dense compacts of the present study, the model predicts a factor of 1.28 increase in pore size, compared to the factor of 1.27, which is experimentally observed. Interestingly, a common, constant factor of 1.27 can also be observed in pore growth data reported by a number of other researchers.