Effect of Piperidin-4-ones on the Corrosion Inhibition of Mild Steel in 1 N H₂SO₄

Table 5

Polarization parameters for mild steel in 1 N H₂SO₄ in the absence and presence of different concentrations of variously substituted piperidin-4-ones.

Inhibitor	Concentration (10^−3 M)	−  (mV vs SCE)	(mA/cm^2)	(mV/dec)	(mV/dec)	Corrosion rate (mmpy)	Inhibition efficiency (%)
—	Blank	467	12.85	171	250	292.24	Nil
(01)	0.4	454	04.37	133	250	099.25	66.03
	1	462	03.03	133	225	068.82	76.44
	2	456	02.53	116	225	057.51	80.32
(02)	0.4	476	06.25	170	229	142.15	51.35
	1	471	03.83	155	221	087.04	70.21
	2	465	03.55	145	229	080.67	72.39
(03)	0.4	472	08.04	162	266	182.70	37.47
	1	467	06.03	145	250	137.00	53.11
	2	479	04.33	125	225	098.34	66.34
(04)	0.4	445	10.09	154	291	229.47	21.46
	1	476	07.80	180	266	177.31	39.31
	2	477	05.92	145	250	134.50	53.96
(05)	0.4	456	08.71	133	250	198.03	32.22
	1	458	07.05	155	266	160.23	45.16
	2	475	05.70	145	208	129.58	55.65
(06)	0.4	476	07.23	142	250	164.34	43.75
	1	463	05.12	142	250	116.34	60.18
	2	469	03.87	154	238	088.05	69.86