Table 1 Electrochemical elemen ts attained from the EIS spectra of the reinforcing steel in SCP solution with 3.5 wt.% NaCl in the existence of 12, 24, 37, 50 μmol L−1 of BTC corrosion inhibitor at variable pH values.
Inhibitor concertation (µmol L−1) | Rct, Ω cm2 | Y × 10−6 sn ohm−1 cm−2 | n | Cdl, × 10−5 F | Inhibition efficiency (IE%) | Surface coverage (ϴ) | Goodness of fit (χ2) | |
|---|---|---|---|---|---|---|---|---|
pH = 7 | Blank | 377 ± 5.3 | 96 ± 22 | 0.88 ± 0.02 | 6.1 | — | — | 2.1 × 10−5 |
12 | 461 ± 42 | 78 ± 10 | 0.84 ± 0.11 | 4.1 | 18 | 0.18 | 1.5 × 10−5 | |
24 | 637 ± 52 | 70 ± 12 | 0.81 ± 0.08 | 3.4 | 41 | 0.41 | 3.4 × 10−6 | |
37 | 924 ± 28 | 66 ± 6 | 0.78 ± 0.12 | 3.1 | 59 | 0.59 | 5.2 × 10−5 | |
50 | 1362 ± 100 | 59 ± 8 | 0.75 ± 0.21 | 2.5 | 72 | 0.72 | 1.8 × 10−5 | |
pH = 10 | Blank | 643 ± 18 | 89 ± 11 | 0.85 ± 0.02 | 5.3 | — | — | 6.5 × 10−6 |
12 | 863 ± 24 | 74 ± 15 | 0.81 ± 0.09 | 3.8 | 25 | 0.25 | 4.2 × 10−5 | |
24 | 1349 ± 31 | 61 ± 17 | 0.80 ± 0.03 | 3.2 | 52 | 0.52 | 1.1 × 10−4 | |
37 | 1953 ± 52 | 50 ± 13 | 0.79 ± 0.05 | 2.7 | 67 | 0.67 | 2.4 × 10−6 | |
50 | 3105 ± 120 | 44 ± 28 | 0.72 ± 0.12 | 2.1 | 79 | 0.79 | 1.1 × 10−5 | |
pH = 12.5 | Blank | 960 ± 66 | 80 ± 32 | 0.82 ± 0.06 | 4.5 | — | — | 8.1 × 10−5 |
12 | 2678 ± 133 | 64 ± 9 | 0.75 ± 0.13 | 3.5 | 64 | 0.64 | 7.7 × 10−6 | |
24 | 5009 ± 149 | 49 ± 15 | 0.72 ± 0.09 | 2.8 | 80 | 0.80 | 3.6 × 10−5 | |
37 | 7680 ± 352 | 39 ± 10 | 0.66 ± 0.17 | 2.1 | 87 | 0.87 | 8.1 × 10−6 | |
50 | 10526 ± 420 | 28 ± 15 | 0.56 ± 0.27 | 1.1 | 91 | 0.91 | 1.9 × 10−5 |
