Experimental validation of a new model for the initial stage of sintering of single phase systems

The progressive smoothing out of surface curvature gradients during the initial stage of sintering of Cu particles is analysed by comparing X-ray microtomography measurements with the predictions of a new model for representing the growth of the necks in a random packing with non-integer average particle coordination. Excellent agreement is found between the measured and computed evolution of interface areas. The analysis reveals that the transition to the intermediate sintering stage (where uniform curvature prevails) occurs where porosity has decreased from similar to 32% initially to similar to 17%. Close to this transition, the model appears to overestimate the solid/vapour area by a few per cent. The nature of the different driving forces is discussed. The validity of the model for the intermediate stage is assessed by comparison with predictions of other models. The effect of particle size distribution on average particle area measurements is estimated from the ratio of shape parameters derived from X-ray tomography measurements. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.