Journal of Oil Palm Research Vol. 29 (1) March 2017, p. 97-109

CORROSION INHIBITION OF MILD STEEL IN HYDROCHLORIC ACID SOLUTION USING FATTY ACID DERIVATIVES

MOHD, N K*; MARIYAM JAMEELAH GHAZALI**; YEONG SHOOT KIAN*; NOR AZOWA IBRAHIMǂ; WAN MD ZIN WAN YUNUSǂǂ; SITI MARIAM MOHD NORǂ and ZAINAB IDRIS*

DOI: https://doi.org/10.21894/jopr.2017.2901.11
ABSTRACT

The inhibitive actions of fatty acid derivatives namely palmitate hydrazide (PH), N-ethylidene palmitate hydrazide (EPH) and N-phenylmethylidene palmitate hydrazide (PPH) on mild steel in 1 M hydrochloric acid were investigated using open circuit potential, linear polarisation and electrochemical impedance spectroscopy techniques. It was observed that the percentage of inhibition efficiency (η%) increased with increasing concentrations of inhibitor and temperature of test medium. The maximum η% approaches 85% in the presence of 200 mg litre-1 of inhibitors EPH and PPH at 308 ± 1K. The inhibitor efficiencies were found to be in the following order: PPH>EPH>PH. The adsorption of these inhibitors on mild steel surface obeys Langmuir adsorption isotherm. They act as mixed-type inhibitors. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX) was also carried out on polished mild steel coupons and those immersed in the test medium with the absence and presence of 200 mg litre-1 of the inhibitors studied.

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* Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia. E-mail: