Ti-Al-doped MoS2 coatings on M50 steel for superior tribological applications

This study used the RF magnetron sputtering technique to deposit titanium and aluminium-doped MoS2 coatings onto M50 steel substrates. The surface morphology and structural properties of the coatings were analysed using FESEM and XRD, respectively. Different vibrational modes present in the samples were analysed using Raman spectroscopy. Energy Dispersive Spectroscopy confirms the presence of Ti and Al in MoS2 coatings. The mechanical properties, including scratch hardness and critical load of failure, were investigated via a scratch tester with a Rockwell C diamond indenter. The Ti-Al-doped MoS2 coating exhibited the maximum scratch hardness of 15.49 GPa and the highest critical load of failure of 20 N. Tribological properties of the coatings were assessed on a multifunctional tribometer under loads ranging from 200 to 600 mN. The films exhibited friction coefficients ranging from 0.028 and 0.003. The wear properties are also assessed using a multifunctional tribometer under applied loads of 200 mN, 400 mN, and 600 mN. The wear rate increased with the applied load, ranging from a minimum of 13.5x 10(-4) mm(3)/Nm at 200 mN to a maximum of 130 x 10(-4) mm(3)/Nm for the Ti-Al-doped MoS2 film at 600 mN.