Table 2.
Chemical composition of the gels after application on different bronze substrates. Results of EDS analyses showing the elemental composition of the gel systems as prepared and after 100 min of application on the metal bronze surface, on a pure cuprite layer and on the green patina developed in 15 years at Tharros (results in weight%, n.d. = not detected). The Cu content in the gel was significantly higher after the cleaning of the green patina, thus proving the selectivity of the gel system toward Cu(II) compounds. The gel was also effective in solubilizing Sn ions and terrigenous elements.
| C | O | Na | Si | Cu | Sn | Al | Fe | Mg | K | Ca | Cl | P | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gel | 56.1 | 38.1 | 5.3 | 0.5 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| Gel applied on the bronze alloy | 57.5 | 37.1 | 4.7 | 0.6 | 0.1 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| Gel applied on the cuprite | 54.6 | 38.4 | 6.0 | 0.3 | 0.3 | 0.4 | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. | n.d. |
| Gel applied on the green corrosion patina (PTh15_insitu) | 28.7 | 37.9 | 8.1 | 7.9 | 5.8 | 3.9 | 3.2 | 2.3 | 0.6 | 0.9 | 0.3 | 0.3 | 0.1 |