Abstract
Fe green and sintered compacts with relative densities of about 70-90% and with size of mainly 3.2×12×15mm3 were nitrided by heating in NH3+H2 (1:1) flowing mixed gas at 923 K for 3.6-14.4ks. These two kinds of compacts could be almost completely nitrided to Fe4N by heating for 14.4ks. The relative densities of nitrided compacts, however, were 76-77% which were lower than those before nitriding. This was because the linear expansion up to about 11-12 % for green compact and 6-7% for sintered compact occured mainly due to crack generation. The saturation magnetizaion of two kinds of nitrided compacts were both about 170-175 emu/g, which was about 80% of the value of Fe solid.
