Corrosion Inhibition of Mild Steel in 1 mol L⁻¹ HCl Using Gum Exudates of Azadirachta indica

Table 1

Corrosion parameters for different concentrations of GAI on mild steel in 1 mol L⁻¹ HCl for various immersion periods at 303, 313, and 323 K.

Time (hours)	C (ppm)	303 K		313 K		323 K
		IE; (%)	CR (mmpy)	IE; (%)	CR; (mmpy)	IE; (%)	CR; (mmpy)
1	Blank	—	0.0136	—	0.0197	—	0.0552
	10	30.56	0.0095	32.69	0.0132	64.38	0.0197
	20	38.89	0.0083	40.38	0.0117	69.86	0.0166
	40	55.56	0.0060	50.00	0.0098	79.45	0.0113
	60	63.89	0.0049	57.69	0.0083	79.45	0.0113
2	Blank	—	0.0085	—	0.0163	—	0.0590
	10	44.44	0.0047	46.51	0.0087	67.63	0.0191
	20	48.89	0.0043	53.49	0.0076	76.60	0.0138
	40	53.33	0.0040	69.77	0.0049	82.05	0.0106
	60	68.88	0.0026	72.09	0.0045	83.33	0.0098
4	Blank	—	0.0071	—	0.0208	—	0.0662
	10	30.67	0.0049	62.27	0.0078	79.71	0.0134
	20	34.66	0.0046	69.09	0.0064	88.71	0.0075
	40	49.33	0.0036	71.82	0.0059	89.71	0.0068
	60	56.00	0.0034	74.55	0.0053	90.29	0.0064
6	Blank	—	0.0066	—	0.0179	—	0.0179
	10	49.04	0.0033	68.66	0.0051	86.14	0.0051
	20	51.92	0.0032	73.94	0.0047	89.86	0.0047
	40	48.07	0.0034	75.35	0.0044	90.56	0.0044
	60	59.62	0.0026	77.82	0.0040	90.36	0.0040
12	Blank	—	0.0044	—	0.0209	—	0.0691
	10	51.77	0.0021	70.18	0.0061	86.37	0.0094
	20	54.61	0.0020	79.97	0.0042	87.05	0.0089
	40	58.87	0.0018	84.19	0.0033	91.29	0.0060
	60	57.45	0.0019	87.05	0.0027	92.11	0.0055