Wear And Friction Behavior Of Tib(2)Thin Film-Coated Aisi 52100 Steels Under The Lubricated Condition

Magnetron-sputtered physical vapor deposited (PVD) thin-film TiB(2)coatings were investigated as a wear-resistant cam tappet coating that runs under the boundary lubrication regime in internal combustion engines (ICEs). AISI 52100 samples with a high negative bias were coated at RF powers of 150, 170, and 190 W. Coatings were characterized via nanoindentation, scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDX), X-ray diffraction (XRD), and Raman analysis. Friction and wear behaviors of these coatings were evaluated by tribometer tests at 25 and 50 N loads. Tests and tribochemical analysis showed that thin-film TiB(2)coatings are very effective to reduce the friction coefficient (COF) and wear rate with a hardness value of approximately 30 GPa and elastic modulus of 424 GPa. Therefore, thin-film TiB(2)has been evaluated as a good cam tappet coating for ICEs.