Compaction Kinetics with Liquid-Phase Sintering of W – Ni – Sn Pseudoalloys

A kinetic equation for compaction with liquid phase sintering is found on the basis of rheological sintering theory. Kinetic coefficients of the equation are determined from physicochemical properties of a dispersed system and its components. Compaction kinetics are studied for the system W - Ni - Sn where the liquid phase is eutectic alloy Ni - Sn with the greatest nickel content. It is shown that experimental results are in good agreement with those obtained by the kinetic equation on the coordinates porosity - time. Diffusion coefficient is evaluated for tungsten in melt (67.5 mass pct Ni + 32.5 mass pct Sn): at 1200 C it is 0.113 x 10 exp -5 sq cm/sec for grain diameter L0 = 3 microns. Time dependences are also obtained for the compaction rate and viscosity of the pseudoalloys studied.