Table 2.
Inhibitory efficacy and electrochemical parameters of 1 M HCl corrosion of M-steel without and with addition of different concentrations of NSQN & CSQN at 303 K.
| Medium | Conc. (M) | Ecorr (mV vs. SCE) | i (μA cm−2) | Tafel slopes (mV dec−1) |
Epp (%) | |
|---|---|---|---|---|---|---|
| βc | βa | |||||
| HCl | 1.0 | -470.8 ± 0.3 | 556.5 ± 0.6 | -109.6 | 67.8 | — |
| CSQN | 10–3 | -424.8 ± 0.5 | 049.9 ± 0.4 | -99.2 | 67.3 | 91.1 |
| 10–4 | -402.1 ± 0.6 | 085.6 ± 0.5 | -146.1 | 64.3 | 84.6 | |
| 10–5 | -399.2 ± 0.4 | 135.1 ± 0.5 | -88.8 | 54.7 | 75.7 | |
| 10–6 | -420.1 ± 0.8 | 195.8 ± 0.4 | -77.8 | 64.5 | 65.0 | |
| NSQN | 10–3 | -410.5 ± 0.9 | 030.4 ± 0.2 | -128.5 | 76.5 | 94.5 |
| 10–4 | -410.3 ± 0.9 | 047.2 ± 0.3 | -101.7 | 65.8 | 91.5 | |
| 10–5 | -408.3 ± 0.4 | 057.9 ± 0.1 | -108.1 | 85.2 | 89.6 | |
| 10–6 | -418.2 ± 0.2 | 131.7 ± 0.3 | -67.9 | 88.4 | 76.2 | |