Abstract
Mechanical alloying (MA) in NH3 has been applied to prepare Fe4N powder or Fe16N2 powder, where the two different kinds of iron powder, i.e., electrolytic iron powder and carbonyl iron powder, were used as the starting materials. N and O both in electrolytic iron powder and carbonyl iron powder were detected to increase in accordance with the time-length of MA. For example, after 160 hours of MA there were 12 at% N and 2 at% 0 in the specimen of electrolytic iron powder, and 11.5 at% N and 2.7 at% 0 in the specimen of carbonyl iron powder. In addition, H in the above mentioned electrolytic iron powder was confirmed to be very small amount of 17 ppm. Neither Fe4N nor Fe16N2 were found to exist in the two kinds of mechanically alloyed specimens. However, after annealing treatment, Fe4N was observed in the both specimens, while Fe16N2 was not.
