SUMMARYIn this paper mathematical morphology is applied to describe the microstructural changes of metal powders during sintering. We show which morphological parameters are accessible to rapid and automatic methods. Of these parameters the change in the connectivity number and the concavity number enable the various stages of sintering to be distinguished. Moreover the growth of the necks between powder particles can be followed using a morphological method of analysis to reveal them. This method can be applied to the investigation of the microstructure of any material consisting of convex grains.