Electrochemical and Thermodynamic Investigation on Corrosion Inhibition of C38 Steel in 1M Hydrochloric Acid Using the Hydro-Alcoholic Extract of Used Coffee Grounds

Table 2

Electrochemical parameters of C38 steel in 1 M HCl at different temperature and with different concentrations of HECG.

T(K)	C (g/L)	−Ecorr (mV/SCE)	−βc (mV)	β a (mV)	i corr (µA/cm^2 )	IE (%)	θ
293.15	Blank	467.56	165.1	107.7	471.84	—	—
	0.25	477.53	123.4	142.3	41.16	91.27	0.91
	0.5	463.793	132.9	139.3	32.62	93.08	0.93
	1	495.877	172.4	185.1	29.34	93.78	0.93
	1.5	468.165	142.7	114.6	14.88	96.84	0.96
	2	512.528	244.5	200.7	12.42	97.36	0.97
303.15	Blank	434.966	186.6	114.5	617.13	—	—
	0.25	463.368	104.3	85.4	67.89	88.99	0.89
	0.5	437.249	119.3	71.9	60.00	90.27	0.90
	1	446.862	112.9	74.4	57.40	90.69	0.90
	1.5	422.386	94.9	51.3	34.99	94.33	0.94
	2	483.017	129.1	117.0	29.98	95.14	0.95
313.15	Blank	433.281	131.0	98.7	989.88	—	—
	0.25	473.608	104.8	97.3	116.06	88.27	0.88
	0.5	428.600	131.9	69.9	97.98	90.10	0.90
	1	450.438	117.7	85.3	96.09	90.29	0.90
	1.5	442.139	107.2	58.0	62.95	93.64	0.93
	2	501.132	198.6	222.4	60.00	93.93	0.93
323.15	Blank	440.487	129.1	105.1	1 794.01	—	—
	0.25	453.151	156.9	101.5	230.14	87.17	0.87
	0.5	466.388	136.7	110.0	198.26	88.94	0.88
	1	439.245	158.0	91.8	179.23	90.00	0.90
	1.5	465.691	129.1	115.6	150.26	91.62	0.91
	2	512.063	288.3	444.0	130.65	92.71	0.92