FORMATION OF Fe-N COMPOUNDS BY LASER NITRIDATION IN AN ATMOSPHERIC AMBIENT
FORMATION OF Fe—N COMPOUNDS BY LASER NITRIDATION IN AN ATMOSPHERIC AMBIENT

The formation of Fe-N compounds by laser nitriding in an atmospheric ambient wasreported. By CW-CO2 laser irradiation on pure ferrite iron in the atmospheric am-bient, Fe-N compounds (including Fe2N, Fe3N and Fe4N) are formed as a result of alaser-enhanced and temperature-enhanced reactions. The samples were analyzed withX-ray diffraction. It is found that the laser power density, scanning speed and nitro-gen temperature are the main factors influencing the formation of Fe-N compounds.Nitrogen can be activated by pre-heating at some temperature. Nitrogen activationand sample surface melting by CW-CO2 laser greatly enhance the reaction betweenthe sample surface and nitrogen beam. After annealing at 500℃ for 3h, some Fe2Nand Fe3N converted into more stable Fe4N.