COMPACT SHRINKAGE DURING LIQUID-PHASE

Preservation of the original particle shape after the reaction with the liquid phase in the course of sintering, indicating that the structures of the solid-phase skeleton from the more refractory component in the starting condition and after s intering are geometrically similar, enables the problem under consideration to be solved with good accuracy. This assumption is made in order to postulate constancy of the ratio between the volume of the interparticle space and the solid-phase particles in the starting condition and after sinterlag, on which our calculation will be based. In principle this ratio may prove to be constant also in the case where, at approximately equal particle sizes, the shape of each particle does change as a result of the reaction with the liquid phase during sintering, but the mean statistical "shrinkage per contact" for all the particles [7] remains the same. Although such an interpretation of the physical picture of liquid-phase sintering would appear to reflect more accurately the real process, the assumption that the shape of the particles remains unchanged after their incomplete dissolution in the melt is preferred because of its greater clarity. Let V A be the volume of the refractory component in the green compact, V B the volume of the lowmelting-point addition, and V 0 the volume of the interpartiele pores. Then the porosity of the compact in the starting condition is