Comparative Study of Palm Oil and Corn Oil as Corrosion Inhibitor for Low Carbon Steel

Abstract

Corrosion can lead to failures in plant infrastructure and machines which are usually costly to repair, contaminating the product and causes environmental damage. Green inhibitor is a corrosion inhibitor which normally comes from the extract of plants and can inhibit corrosion by using chemisorption and/or physisorption mechanism on the metal surface or reacting with metal ions and forming a barrier-type precipitate on its surface. This paper discusses the corrosion inhibition of low carbon steel by addition of palm oil and corn oil as green inhibitors. We also compared the effect of these inhibitors in water and salt water environment. The corrosion behaviour of the low carbon steel was determined by immersion and electrochemical tests. The immersion test was carried out by immersing the samples in distilled water and 3.5% NaCl solution with and without the inhibitors for 1,2,4,6 and 8 weeks. The concentration of the inhibitors used was 100 g/L for both corn oil and palm oil. Scanning Electron Microscopy, Energy Dispersive Spectroscopy and X-Ray diffractometer were used to analyse the results. Immersion test results show that there is a slight weight gain for low carbon steel immersed in the presence of inhibitors suggesting that there is a thin protective layer formed which act as a barrier towards corrosion. Corn oil inhibitor in distilled water shows the highest inhibition efficiency. Its inhibition efficiency is 93.9%, which is slightly higher than palm oil (91.5%) in similar environment.