Table 5. Effect of Concentration of the Investigated Compounds on the Free Corrosion Potential (Ecorr), Corrosion Current Density (icorr), Tafel Slopes (βa and βc), Corrosion Rate (C.R.), Degree of Surface Coverage θ, and Inhibition Efficiency (%IE) for the Corrosion of Carbon Steel in 1.0 M HCl at 25 °C.
| inhibitor | conc. × 10–5 (M) | –Ecorr (Mv) | icorr (μA cm2) | βc (mV dec–1) | βa (mV dec–1) | corrosion rate (CR) (mp y–1) | θ | %IE |
|---|---|---|---|---|---|---|---|---|
| CMBTAP | blank | 420 | 118.5 | 125.77 | 86.8 | 55.36 | ||
| 1 | 425 | 78.94 | 116.9 | 100.16 | 40.7 | 0.333 | 33.3 | |
| 5 | 441 | 75.8 | 79.12 | 100.04 | 35.4 | 0.36 | 36 | |
| 10 | 445 | 67.9 | 78.96 | 96.9 | 31.72 | 0.427 | 42.7 | |
| 15 | 449 | 52.9 | 71.89 | 89.7 | 24.7 | 0.553 | 55.3 | |
| 20 | 453 | 38.18 | 78.24 | 93.8 | 17.8 | 0.677 | 67.7 | |
| CBAN | 1 | 423 | 86.12 | 126.1 | 89.4 | 42.4 | 0.273 | 27.3 |
| 5 | 430 | 80.1 | 99.74 | 87.7 | 37.65 | 0.325 | 32.5 | |
| 10 | 439 | 75.8 | 99.1 | 102.9 | 35.4 | 0.36 | 36 | |
| 15 | 440 | 62.8 | 86.1 | 98.9 | 29.3 | 0.471 | 47.1 | |
| 20 | 431 | 43.15 | 74.07 | 69.48 | 20.08 | 0.605 | 63.5 | |
| CBAMP | 1 | 425 | 78.9 | 95.8 | 90.2 | 36.8 | 0.334 | 33.4 |
| 5 | 430 | 76.67 | 87.6 | 100.3 | 35.3 | 0.359 | 35.9 | |
| 10 | 438 | 73.03 | 101.9 | 95.25 | 33.5 | 0.383 | 38.3 | |
| 15 | 443 | 53.2 | 80.1 | 82.4 | 25.5 | 0.551 | 55.1 | |
| 20 | 447 | 42.8 | 60.5 | 70.66 | 19.9 | 0.64 | 66.4 |