IMPROVING THE TRIBOLOGICAL PROPERTIES OF THE LUBRICANT USING ZnS NANOPARTICLES AS LUBRICANT ADDITIVES

One of the main causes of mechanical parts failure is wear and friction betweenbearing surfaces. There is a lot of interest in the search for novel additives withexcellent tribological characteristics. During this paper, the friction and wear of steelsurfaces are discussed. zinc sulphide nano particles dispersing paraffin oil were usedas lubricating substance. ZnS addition is aimed to reduce the impact friction betweenmetal elements, on friction coefficient and wear of steel test specimens. Theexperiment was conducted using a cross-pin tester. The device consists, mainly, ofrotating and stationary pins of 18 mm diameter and 130 mm long. (10, 15 and 20 N)normal loads are applied by means of weights attached to a loading lever. Therotating specimens are oiled with several percentage of zinc sulphide nano-additives(0, 0.2, 0.4, 0.6, 0.8, 1.0 wt. %) dispersing in paraffin base oil before the test andfurther oil is carried out every 30 sec. during the test. The test time is 5 min. Thefriction force is measured via a digital screen that connects to the load cell. Under anoptical microscope, the scar's diameter is measured to indicate wear, and thecoefficient of friction is computed by dividing the friction force by the normal load.Experiments were carried out at 25 °C using parrafin based oil dispersed by the solidadditives of zinc sulphide nano particles. Experimental results show that 0.4 wt. %Zinc sulphide nano filler added to paraffin oil gives the best anti-friction and wearresistance performance.