In order to study the fundamental mechanism of hot-press sintering, spherical beads of platinum, gold, 30-70 Au-Ag alloy and glass of equal sizes are sintered in a small cylindrical vessel under compressive load. The relations among the diameter of bead, load, sintering time and temperature (the temperature for the beginning of sintering) are determined by the testing method deviced by the author. The values of diameters of beads tested are mainly 0.85 mm, and for investigation of particle size effect 1.35 and 0.45 mm diameters are also used.
The rate of lowering of "the lowest sintering temperature" with the increase of load keeping the sintering time and the radius of bead constant has a maximum value in the range of recrystallization temperature of each metal or softening point of glass.
By the theoretical formula on the adhered area of glass, it is shown that the viscous flow is the rate-determining mechanism in hot-press sintering of glass.
The activation energy to effect hot-press sintering changes with temperature and load. It becomes smaller with temperature, but has a minimum value within the range of recrystallization temperature of each metal or softening point of glass, and then it becomes larger.
It is shown by this report that the recrystallization phenomena plays a prime role in hot-press sintering.

The twentieth anniversary memorial volume