Laboratory for the Study and Development of Innovative Treatments and Heritage Coatings – LETRIP

The protection and conservation of cultural heritage objects (archaeological, museum, monuments, statuary, etc.) is a major societal issue. These are subject to alterations due to interactions with the environment. This is particularly true for metals (iron - steel, brass - bronze, lead, etc.) that corrode. The implementation of effective restoration and protection treatments is therefore crucial. However, these cannot be simple transpositions of solutions used in the anti-corrosion treatment industry. Indeed, there are specific requirements for the heritage to preserve the appearance of objects during treatment and to ensure the reversibility of the coatings applied. In addition, these long-term systems have specific physico-chemical characteristics (heterogeneity, reactivity,...). Thus, both restoration treatments and protective coatings must be the subject of adapted research involving multi-scale characterization techniques and tests representative of the conditions of use.
A-CORROS is specialized in the development and use of these treatments. It has developed a dechlorination prototype unique in Europe, an essential step in the subcritical processing of archaeological metals. In addition, A-CORROS, like all heritage actors, uses a certain number of protective coatings applying them to the statuary exposed in the open air.
In addition, the NIMBE/LAPA (Archaeomaterials and Alteration Prediction Laboratory) has been developing fundamental research on the long-term corrosion of metals and their protection in the heritage for fifteen years. They are based on fine characterization techniques from nano to micrometer (Raman, µXRD, FESEM, TEM, XAS, STXM) and on the re-corrosion of old systems in isotopic environments, in order to identify the processes involved.
The two partners began their collaboration in 2012 with the conduct of a thesis and then the implementation of a joint laboratory. Since December 2015, the LETRIP labcom (Laboratory for the Study of Innovative Treatments and Coatings for Heritage) has been associating the NIMBE/LAPA laboratory and the company A-Corros for research projects developed in the context of the conservation and restoration of metal heritage objects along two axes around 1/ Stabilization by dechlorination of archaeological objects through the use of treatment under subcritical conditions and 2/ Protection of metal objects exposed to the air (museum or outdoor) against atmospheric corrosion through the application of organic coatings. Its objective was to combine A-CORROS' experimental prototypes and conservation/restoration skills with those of LAPA's fundamental research in order to produce R&D on the two research axes defined at the time of its creation.
As part of the first phase of the LETRIP labcom, the results of the research made it possible to commercialize an innovative process for dechlorinating ferrous archaeological objects, allowing a first spin-off for A-Corros. In addition, the research carried out under Axis 2 has highlighted the effectiveness of certain non-toxic compounds on the atmospheric protection of copper objects under immersion application conditions.
For the continuation of the project, emphasis will be placed on optimizing the dechlorination parameters of copper objects for axis 1 in order to commercialize the A-Corros process for this type of object. The determination of innovative applicability conditions for organic coatings using sol-gel processes will be implemented in axis 2 thanks to the support of two PhD thesis funding obtained thanks to the results of the first phase. The progress of this project will place A-Corros at the forefront of metal heritage protection treatments.