Increasing environmental awareness and demanding low energy consumption are of the top priorities for future vehicles manufacturing companies. This can be achieved by reducing wear and friction of engine components, so that its efficiency and lifetime can be increased. Surface treatments and coatings contribute to a better lubrication with oils and can participate significantly in achieving these goals. In this paper, diamond-like carbon (DLC) coating has been incorporated to the vehicle piston rings with different RF powers using magnetron sputtering method. The tribological properties like wear and coefficient of friction have been analysed using Pin-on-Disk tribometer. Micro-hardness and nano-hardness of the coated piston rings were characterized by micro-indentor and nano-indentation processes. Surface microstructure and elemental compositions were observed using Scanning Electron Microscopy. Experimental results demonstrated that the DLC coating shows lower wear and friction under similar operating conditions as compared to uncoated piston rings. Thus, usage of DLC coating has enhanced the engine life time. Silicon interlayer has also been applied between nitrided piston rings and DLC layer in order to have better coating adhesion. The properties of the interlayer are not studied but usage of it is found to protect DLC coating from delamination.

This work concerns microstructural and mechanical properties of an austempered ductile cast iron (ADI). The ductile iron material was produced by the sand mould casting technique. Afterwards, austempering heat treatment was applied to the specimens at two different temperatures of 250°C and 350°C. Austempered Ductile Irons (ADIs) were produced successfully by different two-stage heat treatments, to obtain favorable microstructure and hardness. The microstructure and hardness obtained by such variable heat treatments were compared. The austempering temperature and time were found to be decisive parameters in obtaining a desired ADI microstructure.