Research Article
The Electropolishing of C-Steel in Orthophosphoric Acid Containing Methanolic Plant Extract
Table 2
Limiting current values for C-steel dissolution in 8 M H3PO4 acid in the absence and presence of natural extracts at several temperatures.
| Natural compound | Conc. (ppm) | 25°C | 35°C | 45°C | 55°C | | IE% | | IE% | | IE% | | IE% |
| Marjoram (Origanum majorana) | 0.00 | 0.500 | | 0.560 | | 0.670 | | 0.750 | | 100 | 0.224 | 55.2 | 0.30 | 46.43 | 0.366 | 45.36 | 0.49 | 34.67 | 200 | 0.193 | 61.4 | 0.245 | 56.25 | 0.302 | 54.93 | 0.43 | 42.67 | 300 | 0.154 | 69.2 | 0.194 | 65.36 | 0.262 | 60.90 | 0.321 | 57.20 | 400 | 0.122 | 75.6 | 0.166 | 70.36 | 0.243 | 63.73 | 0.283 | 62.27 | 500 | 0.104 | 79.2 | 0.142 | 74.64 | 0.203 | 69.70 | 0.262 | 65.07 | 800 | 0.083 | 83.4 | 0.122 | 78.21 | 0.176 | 73.73 | 0.241 | 67.87 | 1200 | 0.072 | 85.6 | 0.105 | 81.25 | 0.156 | 76.72 | 0.223 | 70.27 | 1500 | 0.052 | 89.6 | 0.088 | 84.29 | 0.132 | 80.30 | 0.193 | 74.27 | 1800 | 0.033 | 93.4 | 0.065 | 88.39 | 0.103 | 84.63 | 0.167 | 77.73 |
| Coriander (Coriandrum sativum) seeds | 0.00 | 0.500 | | 0.560 | | 0.670 | | 0.750 | | 100 | 0.275 | 45.0 | 0.333 | 40.54 | 0.440 | 34.33 | 0.525 | 30.00 | 200 | 0.214 | 57.2 | 0.278 | 50.36 | 0.365 | 45.52 | 0.465 | 38.00 | 300 | 0.166 | 66.8 | 0.223 | 60.18 | 0.306 | 54.33 | 0.378 | 49.60 | 400 | 0.135 | 73.0 | 0.221 | 60.54 | 0.276 | 58.81 | 0.322 | 57.07 | 500 | 0.113 | 77.4 | 0.186 | 66.79 | 0.245 | 63.43 | 0.281 | 62.53 | 800 | 0.102 | 79.6 | 0.162 | 71.07 | 0.213 | 68.21 | 0.263 | 64.93 | 1200 | 0.093 | 81.4 | 0.143 | 74.46 | 0.184 | 72.54 | 0.243 | 67.60 | 1500 | 0.082 | 83.6 | 0.125 | 77.68 | 0.162 | 75.82 | 0.223 | 70.27 | 1800 | 0.062 | 87.6 | 0.096 | 82.86 | 0.142 | 78.81 | 0.204 | 72.80 |
| Chamomile (Matricaria recutita) | 0.00 | 0.500 | | 0.560 | | 0.670 | | 0.750 | | 100 | 0.325 | 35.0 | 0.378 | 32.50 | 0.463 | 30.90 | 0.543 | 27.60 | 200 | 0.232 | 53.6 | 0.305 | 45.54 | 0.375 | 44.03 | 0.502 | 33.07 | 300 | 0.183 | 63.4 | 0.265 | 52.68 | 0.322 | 51.94 | 0.445 | 40.67 | 400 | 0.156 | 68.8 | 0.242 | 56.79 | 0.292 | 56.42 | 0.402 | 46.40 | 500 | 0.135 | 73.0 | 0.209 | 62.68 | 0.262 | 60.90 | 0.364 | 51.47 | 800 | 0.123 | 75.4 | 0.189 | 66.25 | 0.242 | 63.88 | 0.315 | 58.00 | 1200 | 0.108 | 78.4 | 0.165 | 70.54 | 0.212 | 68.36 | 0.278 | 62.93 | 1500 | 0.122 | 75.6 | 0.176 | 68.57 | 0.225 | 66.42 | 0.302 | 59.73 | 1800 | 0.136 | 72.8 | 0.206 | 63.21 | 0.258 | 61.49 | 0.335 | 55.33 |
| Guava leaves (Psidium guajava L) | 0.00 | 0.500 | | 0.560 | | 0.670 | | 0.750 | | 100 | 0.372 | 25.6 | 0.405 | 28.21 | 0.502 | 25.07 | 0.572 | 23.73 | 200 | 0.335 | 33.0 | 0.362 | 35.68 | 0.445 | 33.58 | 0.543 | 27.60 | 300 | 0.273 | 45.4 | 0.322 | 42.50 | 0.387 | 42.24 | 0.502 | 33.07 | 400 | 0.254 | 49.2 | 0.296 | 47.14 | 0.362 | 45.97 | 0.456 | 39.20 | 500 | 0.186 | 62.8 | 0.242 | 56.79 | 0.333 | 50.30 | 0.425 | 43.33 | 800 | 0.155 | 69.0 | 0.225 | 59.82 | 0.306 | 54.33 | 0.387 | 48.40 | 1200 | 0.134 | 73.2 | 0.203 | 63.75 | 0.283 | 57.76 | 0.342 | 54.40 | 1500 | 0.152 | 69.6 | 0.228 | 59.29 | 0.318 | 52.54 | 0.366 | 51.20 | 1800 | 0.167 | 66.6 | 0.253 | 54.82 | 0.345 | 51.49 | 0.393 | 47.60 |
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