A STUDY OF CORROSION INHIBITON EFFECT OF THIOSEMICARBAZIDE BASED SCHIFF BASE ON ALUMINIUM METAL IN ACIDIC MEDIUM

Abstract

Corrosion is the destruction of metal surface by the reaction with its environment (humidity, gases, acid, alkaline etc.). In this process metal convert in to the more stable form such as sulphide oxide etc. Corrosion of materials and structures is a hindrance to the development of society as it causes significant loss to the economy, leads to pollution, and leads to serious disasters, hence its prevention and control is of great benefit for the humanity. Addition of corrosion inhibitors is one of the practical and easy methods to protect metals and alloys against attack of corrosion in many industrial environments. In this chapter thiosemicarbazide based Schiff base 2-[(3,4-dihydroxy-5-nitrophenyl)methylidene]hydrazine-1-carbothioamide (DHNPMHC) was synthesized and characterized using elemental analysis, FT-IR and UV–Vis methods. The inhibition efficiency of Schiff base DHNPMHC against aluminium corrosion in 0.5 M HCl was examined using mass loss measurement and scanning electron microscopy (SEM). Results showed that DHNPMHC is an effective inhibitor for aluminium corrosion in 0.5 M HCl solution. The inhibition efficiency also increased with concentration of inhibitor increased. Maximum percentage inhibition efficiency 92.6 % (at 4-hour immersion time) is shown at highest concentration of inhibitor 5% (5X10-5M). Adsorption of the inhibitor on the aluminium surface followed Langmuir adsorption isotherm. SEM study of aluminium surface in presence of inhibitor and in absence of inhibitor also supports the inhibition of corrosion in acidic medium. All results show that the Schiff base of thiosemicarbazide (DHNPMHC) is excellent corrosion inhibitor for aluminium in 0.5 M HCl.