Tribological behavior of nanotwinned TiBN coatings

The nanotwinned TiBN coatings with different B content were deposited by magnetron sputtering system, we performed a basic characterization of the structural and mechanical properties of the coatings and compared the tribological behaviors of the TiN coating with those of the nanotwinned TiBN coatings using a ball-on-disk wear test. The results showed that: the nanotwinned TiBN coatings had a nanocomposite structure with nanocolumnar TiN embedded in an amorphous BN and TiB2 matrix, and the columnar structure was continuously refined with the increase of B content. Compared with TiN coating, the maximum hardness of nanotwinned TiBN coating increased by about 45%, reaching 45.1 GPa, and the wear rate was reduced by an order of magnitude compared with that of the TiN coating, exhibiting excellent wear resistance. The enhanced wear resistance may be related to the presence of nanotwinned structure, the nanotwinned structure can bring additional hardening and toughening effects, which inhibit the spalling of the coating during frictional sliding, and the wear mechanism was transformed from the combination of abrasive wear, microcracking and brittle spalling belonging to the TiN coating to polishing wear of the nanotwinned TiBN coating.