Understanding of corrosion inhibition behavior of expired isoniazid modified benzothiazole 2-carboxaldehyde at mild steel/0.5 M H2SO4 interface

Abstract

The corrosion hindering behaviour of (E)-N'-((benzo[d]thiazol-2-yl) methylene) isonicotinohydrazide (BTMIH) was tested on mild steel (MS)/0.5 M H2SO4 interface and established BTMIH as an excellent corrosion retarding agent. Various techniques, viz. electrochemical analyzing, surface studies, contact angle measurement, and gravimetric measurement, have been used to establish the corrosion-resistant behaviour of BTMIH. Thermodynamic and activation parameters obtained from gravimetric studies elucidated the mechanism of corrosion. The increase in charge transfer resistance caused by the presence of BTMIH confirmed its capacitive behaviour. Addition of 7.08 × 10−4 M of BTMIH exhibited 98 % corrosion combating efficiency confirmed by electrochemical impedance spectroscopy (EIS) results. The X-ray photoelectron spectroscopy (XPS) scan confirmed the presence of BTMIH film on the MS surface. The presence of BTMIH in electrolytic solution makes the MS surface hydrophobic towards electrolytic solution as shown by increased contact angle between MS/electrolyte (42.38° with 7.08 × 10−4 M of BTMIH compared to 12.6° with 0.5 M H2SO4). The maximum magnitude of corrosion potential shift (39 mV) established BTMIH as a mixed-type inhibitor.