The invention relates to a method and a device for preparing
iron nitride material by double promotion of nanocrystallization and a strong
magnetic field. An electrical heating body and a
water cooling sleeve are sequentially arranged outside the inner stainless steel wall of the device, and a
magnetic field generating device is arranged outside the
water cooling sleeve. The method for preparing
iron nitride comprises the following steps: firstly, preparing pure nanometer
iron powder or pure nanometer iron films; putting the
iron powder or the iron films into the device; leading in
hydrogen gas; preserving heat for 10-90 minutes at 300-450 DEG C; naturally cooling to 60-100 DEG C, applying a magnetic filed of 6-20 T by the
magnetic field generating device at the temperature, and leading in
ammonia gas at the same time; raising the temperature in a reactor to 120-250 DEG C and preserving for 8-30 hours; and naturally cooling to
room temperature. In the invention, nitridation reaction can be carried out in the condition of low temperature, which is beneficial to the formation of alfa''-Fe16N2 and the inhibition of the generation of other
iron nitride substances. The content of the prepared iron
nitride material alfa''-Fe16N2 reaches 65-99 percent.