Some Thiophene Derivatives as Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid

Table 7

Activation parameters for carbon steel corrosion in the absence and presence of various concentrations of inhibitor (A) in 1 M HCl.

𝐶inh.× 10^−5 (M)	Activation parameters
	𝐸^∗𝑎 (kJ mol^−1)	Δ𝐻^∗ (kJ mol^−1)	Δ𝑆^∗ (J mol^−1K^−1)
Blank	58.50	24274.22	5574.8599
2	39.39	15975.93	1.5162
4	34.38	13798.83	0.1738
6	34.30	13764.91	0.1532
8	27.54	10830.32	0.0086
10	27.20	10682.49	0.0068
12	25.41	8712.32	0.0048