Study of Synergistic Effect of Iodide on the Corrosion Antagonistic Behaviour of a Heterocyclic Phenylhydrazone in Sulphuric Acid Medium on Carbon Steel

Table 1

Inhibition efficiency (𝜂_𝑤%) from gravimetric measurements for different systems on CS corrosion at 24 h in 0.5 M H₂SO₄ at 30°C.

System/conc.	Corrosion rate (𝜈)	% of inhibition efficiency (𝜂𝑤%)
Blank	23.53	—
Blank + 0.2 mM KI	19.40	24.0
0.2 mM 3APPH	27.83	−18.28
0.4 mM 3APPH	32.67	−38.83
0.6 mM 3APPH	44.77	−90.26
0.8 mM 3APPH	45.31	−92.54
1.0 mM 3APPH	45.48	−93.27
0.2 mM 3APPH + 0.2 mM KI	2.84	87.90
0.4 mM 3APPH + 0.2 mM KI	2.50	89.38
0.6 mM 3APPH + 0.2 mM KI	1.06	95.47
0.8 mM 3APPH + 0.2 mM KI	0.99	95.80
1.0 mM 3APPH + 0.2 mM KI	0.82	96.50