Friction and wear behaviour of selected titanium and zirconium based nitride coatings in Na2SO4 aqueous solution under low contact pressure

The low contact pressure friction and wear behaviour of four titanium and zirconium-based nitride coatings were investigated in Na2SO4 electrolyte. The experiments were performed using two different potentiostatic conditions, namely OCP and 0.5 V. For all selected potentials, zirconium-based nitride coatings showed an enhanced wear resistance, when compared to titanium-based coatings. This improved wear performance is due to the formation of stable oxide layers for the selected loading conditions, resulting in low and steady friction. Alternatively, titanium-based coatings were more prone to wear accelerated corrosion, which yielded a high and unstable coefficient of friction accompanied by significantly higher wear.