The use of mixture of piper betle and green tea as a green corrosion inhibitor for API X-52 steel in aerated 3.5 % NaCl solution at various rotation rates

Flow induced corrosion due to the presence of turbulent flow often occurs which causes severe internal thinning and promotes premature leakage. In practice, the common method for controlling such internal high corrosion rate is chemical injection using corrosion inhibitor such as amine based which utilizing adsorption or film forming mechanism. Unfortunately, the protection performance of such inhibitor might be less effective due to turbulent flow induced. The aim of this work is to study the use of mixture of piper betle and green tea as an alternative of green corrosion inhibitor (eco-friendly) to reduce the corrosion rate of API X-52 steel in aerated 3.5 % NaCl solution in turbulent flow condition whether high inhibitor efficiency can be achieved. The method of corrosion rate measurements was conducted using electrochemical polarization equipped with CMS100-Gamry Instruments and DC105 software as well as Rotating Cylinder Electrode (RCE) simulation. The mechanism of inhibition was also investigated using Electrochemical Impedance Spectroscopy (EIS) method with EIS300 software. The results showed that the addition of mixture of 1000 ppm piper betle and 4000 ppm green tea extracts with Reynold number ranging from 0 up to 30000 reduced the corrosion rates significantly with its approximately 90 % inhibitor efficiencies achieved. In addition, EIS spectra showed that in the absence of corrosion inhibitor, the Warburg impedance (diffusion controlled) was significantly attributed to the overall impedance but in the presence of corrosion inhibitor, capacitive impedance (charge transfer controlled) was mainly attributed to the overall impedance.