Fabrication of a Dense Long Rod through Pulse Discharge Sintering Assisted by Traveling Zone Heating

摘要

A traveling zone heating technique was examined with the aim of creating a long dense rod by means of pressurized pulse discharge sintering. Based on local heating enabled by electric power supplied perpendicular to the loading axis through a terminal board, a one-direction continuous sintering process was successfully achieved, in which the terminal board was able to slide along the side wall of the cylinder in the direction of the loading axis while remaining in continuous contact with it. The heating zone was limited to within the range corresponding to the thickness of the board. Aluminum powder of 9.54 g, 99.9 percent in purity with an average size of 20 mu m was placed in a graphite cylinder of inner diameter 15 mm. Electric power was then supplied through a 12 mm thick terminal board to sinter the powder. Power supply was provided to the board, which was moved upwards three times by a distance of 8 mm. A 20 mm long rod with a relative density of 99.2 percent was successfully sintered by means of this procedure. Similarly, four successive local heatings over a range 30 mm wide while moving the heating zone distances of 20 mm led to the production of a 55 mm long aluminum rod with a relative density of 99.7 percent. The present results suggest that much longer rods can be sintered well by expanding the moving range of the heating zone. The new sintering technique proposed in this study will enable the production of long rods with high density.