Tribological behaviors of Fe-Al-Cr-Nb alloyed layer deposited on 45 steel via double glow plasma surface metallurgy technique

Double glow plasma surface metallurgy technique was used to fabricate a Fe-Al-Cr-Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of the Fe-Al-Cr-Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate that the 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the Fe-Al-Cr-Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe-Al-Cr-Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.