The Redipuglia First World War Memorial accommodates thousands of copper-alloy (Cu76-Zn11-Sn5-Pb2, other6) plates with the names of 39,857 identified soldiers who fell in battles in the surrounding areas. Within the framework of a restoration intervention at the site, a test project was planned a few months prior to the beginning of the full restoration in order to compare surface treatments on coupons with the same alloy composition as the 80-year-old plates. Surface morphology, aesthetic appearance and corrosion rate were characterised by non-destructive techniques both on coupons and on a test plate from the memorial after sandblasting, black artificial patination and application of a protective coating. A widely used microcrystalline wax (Soter) and a micro-crystalline wax blend (CTS) applied in one or two layers were compared on coupons and the test plate. A silane treatment from the B-IMPACT project was also tested on coupons only. The results obtained were compared all along the treatment steps in order to check for the degree of similarity between the treatment effect on the original plate and on the coupons. A higher surface roughness characterised the test plate compared to the coupons after sandblasting, even though the colour difference was negligible, and very similar results were obtained for the corrosion rate, which was just slightly lower on the coupons. The change in colour on the artificial patina was only just perceivable on the coupons and the test plates, with an increase in the corrosion rate. The surface colour on more or less all the tested coatings did not change in any perceivable way with respect to the patinated surface. The improvement in corrosion protection was systematically lower for the test plate with respect to the coupons but identical results were obtained for the wax treatments, the best being the CTS wax blend applied in two layers. The highest protection was obtained on the coupons using the B-IMPACT silane coating. The treated coupons were exposed to natural weathering at the Genoa Experimental Marine Station. The results obtained helped and supported the choice of treatment to be adopted for the Redipuglia plates.
A Multi-Analytical Approach to Evaluate Surface Treatments on Copper-Alloy Artefacts: A Case Study Applied to the Restoration of the Memorial of Redipuglia
Salvadori B;Letardi P
2019
Abstract
The Redipuglia First World War Memorial accommodates thousands of copper-alloy (Cu76-Zn11-Sn5-Pb2, other6) plates with the names of 39,857 identified soldiers who fell in battles in the surrounding areas. Within the framework of a restoration intervention at the site, a test project was planned a few months prior to the beginning of the full restoration in order to compare surface treatments on coupons with the same alloy composition as the 80-year-old plates. Surface morphology, aesthetic appearance and corrosion rate were characterised by non-destructive techniques both on coupons and on a test plate from the memorial after sandblasting, black artificial patination and application of a protective coating. A widely used microcrystalline wax (Soter) and a micro-crystalline wax blend (CTS) applied in one or two layers were compared on coupons and the test plate. A silane treatment from the B-IMPACT project was also tested on coupons only. The results obtained were compared all along the treatment steps in order to check for the degree of similarity between the treatment effect on the original plate and on the coupons. A higher surface roughness characterised the test plate compared to the coupons after sandblasting, even though the colour difference was negligible, and very similar results were obtained for the corrosion rate, which was just slightly lower on the coupons. The change in colour on the artificial patina was only just perceivable on the coupons and the test plates, with an increase in the corrosion rate. The surface colour on more or less all the tested coatings did not change in any perceivable way with respect to the patinated surface. The improvement in corrosion protection was systematically lower for the test plate with respect to the coupons but identical results were obtained for the wax treatments, the best being the CTS wax blend applied in two layers. The highest protection was obtained on the coupons using the B-IMPACT silane coating. The treated coupons were exposed to natural weathering at the Genoa Experimental Marine Station. The results obtained helped and supported the choice of treatment to be adopted for the Redipuglia plates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
