Study on wear and friction resistance of nanocrystalline Fe nitrided at low temperature

► A nanocrystalline surface layer was fabricated on a pure Fe plate by means of a surface mechanical attrition treatment (SMAT). ► The SMAT process is able to enhance gas nitriding kinetics at low temperature. ► The hardness value of the nitrided SMAT sample is about 6.1 GPa at the top surface. ► The friction coefficient decreases and the wear resistance increases with the SMAT sample. ► The improvement in friction and wear properties is attributed to the higher hardness in nanocrystalline nitride layer.