Study of margosa oil (neem oil) added lubricants for automotive tribo-materials

Abstract

A comparative st.udy on physico-chemical properties of palm and margosa oi I blended lubricants and on the corrosion behavior of automotive tribo-materials was conducted. In this work viscosity, density, flash point, fire point, total acid number, lR spectroscopic analysis and electrochemical corrosion were studied. Experimental parameters were: different percentages of palm and margosa oil in lubricants, temperatures and specially for corrosion three different tribomaterials. Viscosity and density of base oil and palm or margosa oil added base oil were decreased with the increase of temperatures. The highest and lowest viscosity found at 30°C and 100°C respectively. At IOpoC, increase of viscosity and density with the increase of palm and margosa oil in lubricating oil was found. Although viscosity and density of margo sa oil blended lubricants were found higher than palm oil blended and 30,40,60, and 80°e. But at 100De. thc palm oil blended lubricant showed higher viscosity and density than margosa oi I blended lubricant. No changes of flash and fire point was found in palm and margo sa oil blended lubricant in this work. The degradation of palm and margo sa oil blended lubricants were studied by the determination of total acid number and IR spectroscopic analysis. Total acid number increased with the increase of oxidation (heating) time. The highest total acid number was found for 8% palm and margosa oil added lubricants after 24 hours oxidation. Comparison of palm and margosa oil blended lubricants, showed high acid value for margosa added lubricants at all times. Larger changes of margosa oil blended lubricants than palm oil blended lubricant wcre found from the IR spectroscopic analysis of 8% palm and margosa oil blended lubricants. Electrochemical corrOSIOn behavior of three tribo-materials was studied oy potentiostatic method at 30, 40 and 60°C. The corrosion rate of 0: 16% and 0.79% carbon steel increase with the increase of palm oil percentage in the lubricating oil at all temperature. Corrosion rate of brass was negligible in all palm blended lubricants at all temperature. From the comparison of corrosion characteristic of different palm oil blended lubricants, it is found that 2% palm oil has the h'ighest inhibiting property among the three tribo-metals under. study. But in margo sa oil added lubricants the corrosion rate of 0.16°1<, and 0.79'!() caroon steel increases with the increase of margosa oil upto 6% at all temperature. However, at 60°C, 8% margosa oil blended lubricating oil showed the highest inhibiting property than other margosa oil blended lubricating oil. Although 8% margosa oil blended shows the general character at room temperature. In the case of brass alloy a steady corrosIOn rate was observed at all temperature in all types of margosa blended lubricants. At room temperature slightly increased corrosion current was observed at higher potential. Comparison of corrosion behavior of palm and margosa oil blended lubricating oil showed that any percentages of palm oil blended lubricants showed better inhibiting property than the corresponding margosa oil blended lubricant. 2% palm oil added lubricant showed the highest corrosion inhibition at all temperature for three tribo-materials under study. At 60°C, 8% margosa oil added lubricant showed significant inhibiting character than any other margosa oil blended lubricants.