Effects of Immersion Time and 5-Phenyl-1H-tetrazole on the Corrosion and Corrosion Mitigation of Cobalt Free Maraging Steel in 0.5 M Sulfuric Acid Pickling Solutions

Table 1

Corrosion parameters obtained from the potentiodynamic polarization curves shown in Figures 1, 2, and 3 for maraging steel electrode that has been immersed for different exposure intervals in 0.5 M H₂SO₄ containing different PHTA concentrations.

Medium	Parameter
	𝛽𝑐	𝐸Corr	𝑗Corr	𝛽𝑎	𝑅𝑝	𝑅Corr	IE
	(mVdec^−1)	(mV)	(𝜇A cm^−2)	(mVdec^−1)	(Ω cm^2)	(mmy^−1)	(%)
0.5 M H2SO4 (0 min)	−135	−300	1900	35	0.011	22.09	—
+1.0 mM PHTA (0 min)	−135	−283	880	28	0.017	10.23	54
+5.0 mM PHTA (0 min)	−140	−270	670	30	0.025	7.79	65
0.5 M H2SO4 (60 min)	−100	−300	3300	48	0.012	38.37	—
+1.0 mM PHTA (60 min)	−120	−295	1450	50	0.023	16.86	56
+5.0 mM PHTA (60 min)	−105	−265	1050	55	0.028	12.21	68
0.5 M H2SO4 (120 min)	−95	−290	4300	55	0.013	49.99	—
+1.0 mM PHTA (120 min)	−100	−280	1720	58	0.029	17.00	60
+5.0 mM PHTA (120 min)	−122	−275	1190	60	0.039	13.84	72