Using electrochemical testing and modeling to assess the efficiency of a water-soluble inhibitor on the corrosion of 6061Al-15 % (v) SiC (p) composite

Abstract The corrosion behaviour of 6061Al-15 % (v) SiC (P) composite was investigated in a 0.5 M HCl medium using electrochemical techniques. A water-soluble inhibitor, N-(1-morpholinobenzyl) semicarbazide (NMSc), was synthesised to test its corrosion inhibition activity on 6061Al-15 % (v) SiC (P) composite. The inhibitor showed cathodic-type behaviour and 95.42 % inhibition efficiency at 2.56 mM concentration and 303 K temperature. The thermodynamic results revealed the inhibitor’s physisorption, which followed Langmuir’s isotherm model. A drastic reduction in corrosion current density in the inhibited medium indicates that the inhibitor effectively controls the deterioration of the composite in the HCl medium. A significant rise in polarisation resistance on increasing inhibitor concentration offers greater resistance for the charge transfer process, ensuring better control over the composite corrosion. The surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirms the inhibitor film formation on the composite. The quantum chemical theoretical calculations supported the electrochemical results.