a pressure of 1 5 atoms was supplied into the vessel the ball mill vessel was rotated at 440 rpm this treatment intended to cause the reaction described as the following formula it took 50 hours to react a whole amount of ammonia gas in the vessel with iron powders on condition that the rotation speed is 440 rpm fig1 shows x ray diffraction pattern of pure iron u03b1 fe powder which is not reacted with nitrogen in fig1 u03b8is twice an incident angle u03b8 as described in fig8 fig9 illustrates the crystallographic planes for cubic unit cells fig2 shows x ray diffraction pattern of a resulting powder sample in which the above mentioned treatment was performed 8 times as compared with pure iron the structure of the resulting powder is identified as bcc and the diffraction lines shifted to a small angle side these data show that nitrogen atoms have dissolved in u03b1 fe and expand its lattice fig3 shows an enlarged view of the above x ray diffraction pattern of fe 110 the average amount of nitrogen of iron nitride powder at this stage is about 10 at as nitrogen is hardly dissolved into u03b1 fe at room temperature it is considered that nitrogen atoms are super saturated within the iron of bcc crystal structure fig4 shows.