Garcinia indica as an Environmentally Safe Corrosion Inhibitor for Aluminium in 0.5 M Phosphoric Acid

Table 1

Results of Tafel polarization studies on aluminum in 0.5 M phosphoric acid solution containing different concentrations of inhibitor GIE.

Temp.; (°C)	Conc. of inhibitor; (ppm)	𝐸corr; (mV versus SCE)	𝑖corr; (×m A cm^−2)	−𝑏𝑐; (mV dec^−1)	𝑏𝑎; (mV dec^−1)	CR; (mm y^−1)	𝜂; (%)
30	Blank	−797	0.17	637	354	1.89	—
	100	−795	0.09	626	356	1.03	45.33
	200	−805	0.08	634	346	0.91	51.96
	300	−772	0.08	611	361	0.85	54.77
	400	−801	0.06	686	333	0.70	62.99
	500	−785	0.06	664	346	0.63	66.58
35	Blank	−793	0.22	610	353	2.39	—
	100	−788	0.11	641	367	1.18	50.64
	200	−779	0.10	674	342	1.06	55.66
	300	−796	0.09	668	365	0.96	59.68
	400	−796	0.07	685	353	0.80	66.70
	500	−764	0.06	632	319	0.71	70.37
40	Blank	−797	0.28	596	364	3.00	—
	100	−774	0.12	615	374	1.34	55.38
	200	−789	0.11	621	373	1.16	61.30
	300	−796	0.10	642	371	1.06	64.56
	400	−777	0.08	670	321	0.84	72.15
	500	−769	0.07	655	299	0.75	75.17
45	Blank	−804	0.40	595	367	4.38	—
	100	−797	0.16	578	397	1.75	60.04
	200	−799	0.14	616	380	1.49	66.01
	300	−793	0.11	642	380	1.24	71.70
	400	−780	0.10	716	312	1.14	74.03
	500	−665	0.08	546	264	0.84	80.84
50	Blank	−800	0.48	579	379	5.20	—
	100	−765	0.16	573	370	1.73	66.75
	200	−806	0.14	586	396	1.56	70.09
	300	−810	0.12	595	392	1.28	75.38
	400	−738	0.09	609	366	1.02	80.44
	500	−639	0.07	616	343	0.75	85.59