The sintering of ingots with different initial densities γ0 is accompanied by a regular increase in compact
density γs with increase of γ0 (Fig. 2a). However, while at γ0 ≤ 5.3 g/cm3 and temperatures 1180-1200°C the density of
the sintered materials noticeably increases, the change of γs with further increase of γ0 is very insignificant. The reason
for this, apparently, is that the capillary pressure and bulk viscosity of the material are related to its porosity.