Project ESR7

Innovative techniques for the assessment of the degradation state of metallic artifacts

Project Description and Objectives

Chemical-physical processes responsible of the degradation of metallic artefacts are well known and widely investigated, however every artefact has a different story strictly related to the environment that was in contact with the work of art. The environmental parameters definitely influence the corrosion process and differently affect the different areas of the metallic artefacts. Sometimes in the same excavation site, similar artefacts buried nearby, are found in rather different conservation conditions. Consequently, it is of outstanding importance for restorers/conservators to assess the state of deterioration of the artefacts: diagnostics has to be carried out with well-tested scientific methodologies, in order to avoid traumatic interventions and then to protect the metallic artefact in a manner suitable for its preservation. The first objective of the research project is the study of the degradation processes undergone by metallic artefacts of archaeological, historical and artistic interest. Given the breadth of the typologies, the investigation will be limited to metallic artefacts made of copper alloys and precious metals. Copper and its alloys have been the first metals used ancient times; they not only are the basis of the tools used for the work or household, but, in some cases, they have also formed a system of semi-precious alloys (Orichalcum for the Romans), and, finally, are the basis of all the statuary monumental bronzes. Gold jewellery is a sophisticated ancient art form among the most refined and delicate; the ancient coinage, whose study is used to achieve a thorough understanding of the social and economic situation of a historical period.

The innovation degree of the project lies in the idea of developing different skills: from materials science, to surface science and metallurgy. The joint work, carried out with different techniques, has the purpose of defining a methodology less invasive as possible able to provide the state of degradation of the artefact.

The second objective is to determine the best experimental methods that allow to preserve the artefacts after it has been restored, by studying the processes of passivation of the surface and the protection coating that are given, that by monitoring the state of the artefact with periodic checks of its state of conservation.

Expected Results:
The work will therefore be divided in the several steps:
1) selection and characterization of the metallic artefacts of archaeological interest to be investigated in cooperation with the Museo Egizio Torino;
2) production of reference alloys of micro-chemical and microstructural composition similar to the ones of the chosen metallic artefacts (3 copper based alloys, 3 silver-based alloys);
3) accelerated aging of the reference samples in climatic chamber in the soil coming from the excavation sites, with electrochemical techniques;
4) characterization of the patinas and the corrosion products by means of XRD, XRF, optical microscopy, SEM, Raman spectroscopy;
5) deposition of protective coatings, SiO2-like, by means of PECVD (plasma enhanced chemical vapor deposition) techniques;
6) evaluation of the protective effectiveness of the coatings by means of electrochemical impedance techniques (EIS), a versatile technique that can be utilized also for the characterization of the barrier effect of the patinas;
7) Validation of the methodology on the metallic artefacts.

The expected results are: the production of reference alloys, definition of investigation methodologies with portable instruments too, production of optimized SiO₂-like layers with high barrier effect, definition of a monitoring procedure with electrochemical impedance spectroscopy with a portable instrument.

Type of Contract and Benefits

The selected ESR 7 will be offered a full-time 36 months employment contract by the Polytechnic of Turin (POLITO)

The contract will include the following allowances:

→Living Allowance (LA) = € 3318,37 per month corresponding to the monthly salary for the fellow before any deductions: contributions of both employers and employees to social security, pension, taxation.
→ Family allowance (FA) = 500€ per month. The LA will be paid only if the recruited ESR has a family^* status at the time of recruitment.
→Mobility Allowance (MA) = 600€ per month. The MA is a contribution to household, relocation and travel expenses.

^*"Family" means persons linked to the researcher by marriage (or a relationship with equivalent status to a marriage recognised by the legislation of the country where this relationship was formalised) or dependent children who are actually being maintained by the researcher.

Doctoral Degree

ESR7 will be awarded a joint Double Doctorate degree by the Polytechnic of Turin (POLITO) in cotutelle with the University of Évora (UEVORA).

Additional Secondments to ED-ARCHMAT Beneficiaries and/or Partners could be planned according to ESR7 research needs.

Eligibility Criteria

Main Eligibility criteria are indicated in section ADMISSION RULES

ESR 7 Additional Eligibility Criteria
→ IELTS CERTIFICATE with a minimum score of 5.0;
→ One of the language certificates recognized equivalent to IELTS 5.0 by the Foreign Languages Centre and detained in the table (2018/19) published at the webpage: https://didattica.polito.it/cla/en/certificates/ or a declaration of having a Ba. and/or M.Sc. degree issued by a University in which courses are taught in English, i.e. "The medium of instruction was English". Certificates not included in the list above will not be accepted;
→ Valid GRE® General Test, possessed by the application deadline.

ESR7 Specific Specific Requirements

Master (2^nd cycle equivalent according to the Bologna Process) Degree issued by an officially recognized academic institution which grants admission to PhD programmes in the country of issuance in one of the following fields: Engineering, Materials Engineering, Materials Science, Chemistry, Conservation Science.

Foreign academic degrees and diplomas will be validated and recognized by the authorized personnel of the University of Evora and Polytechnic of Turin before enrolment in the double PhD degree.

Application Deadline

The deadline for the online submission of completed application forms available under section APPLICATION of the ED-ARCHMAT website is 15^th July 2018.