Neck growth on initial stage of pulse current pressure sintering for coarse atomized powder made of cast-iron

Sample temperature and neck growth were investigated on pulse-current pressure sintering of coarse cast-iron powder (diameter: 200 mu m) produced by a gas atomizing technique. At 873 Ii of die temperature, the temperatures of sample inside and its surface were 950 Ii and 910 Ii, respectively. Microstructure observation of the sintered cast-iron revealed that there were no melting and remarkable deformation around the grain interface. Neck growth was governed by plastic deformation during the initial stage of the process. A model calculation of neck growth by assuming the plastic deformation of particles is in good agreement with the experimental results. The results indicate that the initial stage on pulse current pressure sintering is similar to conventional hot-press sintering for coarse cast-iron powder.