We report a study about the effects on magnetic properties of pressure
less sintering without binder addition performed on iron and boron pow
der mixture. The obtained self-supported samples appear highly porous
or very compact depending on the maximum temperature, T(max), reached
during the heating process. They maintain the soft magnetic properties
of original Fe-B powder mixture if T(max) does not exceed a critical
temperature; afterwards the magnetic properties change very abruptly.
A decrease in the magnetization saturation per unit mass, M(s), has be
en observed to increase the T(max) value. Mossbauer spectroscopy has r
evealed the presence of Fe2B boride inside the obtained samples whose
quantity increases with T(max). Considering the magnetic moment per ir
on atom in Fe2B as the theoretical one calculated by Ching et al., it
has been possible to correlate the T(max) dependence of M(s) with the
growing of Fe2B boride. The compacting process seems to be due to the
growth of Fe2B boride between Fe/B interfaces.