Activation of the sintering of iron powder by nickel, cobalt, and manganese additions. I

Summary

• 1. The activating effect of an addition is determined to a large extent by the diffusional mobility of its atoms, and, consequently, additions should undergo reduction or decomposition during sintering with the formation of active metal atoms.

• 2. To secure an effective activation of the solid-phase sintering process, the following conditions must be satisfied:

• a) the atoms of the addition material must be capable of dissolving in the matrix metal under sintering conditions;

• b) the partial diffusion coefficients of the addition and matrix metals should not be equal. The addition metal should have a higher partial coefficient;

• c) when activating additions are used without the aim of reducing shrinkage, the dissolution of the element introduced should not substantially strengthen the contacts between the particles.