Surface microstructures and mechanical properties of TiN coatings irradiated by high current pulsed electron beam

The surfaces of the TiN coatings, synthesized by plasma immersion ion implantationand deposition onsubstrate of GCr15 bearing steel, were modified by irradiation of high current pulsed electron beam (HCPEB). The impact of the modification conditions, including but not limited to the acceleration voltage, energy density of electron beam and pulse number, on the microstructures and mechanical behavior of the TiN coatings were investigated with X-ray diffraction, scanning electron microscope, atomic force microscope, and conventional mechanical probes. The results show that the HCPEB irradiation melted the TiN coatings and strongly increased the surface roughness and TiN/substrate interface adhesion; but weakly affected the phase-structures and mechanical/tribological properties. For example, The HCPEB irradiation, at 25 kV and 5 J/cm² for 10 pulses and/or 20 pulses, increasedthe interfacial adhesion and surface roughness of the TiN coatings from 7.4 to 15 N and from 8.5 to 14.5 nm, respectively.