Developing a stigma about this finite action will retard research and limit improvement in treatment design. The way forward is to weigh the advantages against the disadvantages of invasive analysis and testing, with a clear eye on the greater good and the global picture of conservation.
Corrosion and conservation of cultural heritage metallic artefacts
With the support of the custodians of heritage objects, analytical science can provide a major contribution to advancing preservation methods and longevity of heritage objects. Scientists can do much to ensure that invasive sampling is an accepted option by offering clear and distinct research designs and goals, which can be readily interpreted by object custodians and used in the reasoning process that will determine if invasive analysis is appropriate and acceptable. Quality of research, dissemination of outcomes and the impact of research on management practice are all important factors in this decision-making process.
A brief overview of the structure and content of the book reveals the importance and success of various sampling strategies in contributing to our understanding and delivery of conservation. The implementation of invasive analytical methods within a structured methodology, which may range from macro through micro to nano levels of investigation, can deliver information on corrosion mechanisms that will make it possible to decipher the differing parameters controlling alteration kinetics. Providing understanding of the behaviour of the system in this way informs choice of conservation treatment for comparable materials.
Integrating a range of fine analytical techniques that includes methods such as time-resolved spectroelectrochemistry, voltammetry of particles and laser-induced breakdown spectroscopy LIBS supports such investigative analytical studies. The capability of such analytical tools can be discovered in Part II of the book, which is dedicated to analytical techniques and methodologies. The efficiency of these stepped and integrated studies for understanding corrosion systems is provided in Part III via topics that include artistic patinas on bronzes, silver, underwater corrosion, long-term anaerobic corrosion of archaeological iron and reactivity studies within the frame of atmospheric corrosion and industrial structures.
In support of this, a specific part of the book is dedicated to the presentation of recent results or reviews of selected cultural heritage metals and their corrosion. In addition to laboratory studies, it is necessary to generate precise information on environmental conditions and identify their impact on the behaviour of a system, as this will lead to better understanding of the corrosion behaviour of cultural heritage in-situ. Examples of long-term monitoring of archaeological sites are integrated into general studies of corrosion systems within Part III of the book; these include anoxic corrosion of iron and reactivity studies for iron corroding in the atmosphere, and Part IV is entirely dedicated to these issues.
Thus, a chapter in Part IV illustrates how a new measurement system obtains electrochemical data EIS on site, while the importance of monitoring environmental parameters such as oxygen, relative humidity and temperature for understanding corrosion mechanisms is reported in other chapters in Part IV. This includes offering a design for a smart sensor to gather such data in specific heritage contexts like museums and archaeological sites. Once corrosion mechanisms and the behaviour of systems are understood, conservation options and treatment designs can be addressed.
Consequently, Part V is dedicated to reviews and reporting of methods and methodologies applied in conservation.
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These consider the conservation issues holistically to identify, report and critique treatment methods using an interdisciplinary integrated approach with scientific studies at its core. Included here are chapters on: desalination treatments; the use of subcritical fluids to stabilise archaeological ferrous artefacts; display and long-term storage of metals in museums; conservation of shipwrecks; use of protective coatings; inhibitors to protect artefacts; and the challenge of producing standards for testing in conservation science.
As this book illustrates, both laboratory and in-situ studies to investigate and understand corrosion and conservation systems are time consuming and expensive within the poorly financed conservation sector. This is why the relationship between conservators, restorers, corrosion scientists and those specialised in material analysis, should be based on integrated ongoing collaboration and not be seen as a scientific service to conservation.
Protection of historical lead against acetic acid vapour : Koroze a ochrana materialu
To maximise the potential of this collaboration, the community must prioritise issues for scientific research in metallic cultural heritage. This can and must take place within the framework of national or international committees that include representation from all interested and relevant disciplines. There are also opportunities to integrate into international scientific societies to federate groups into heritage research.
This type of collaboration requires proactive action in the forthcoming years if it is to become a reality.
In the absence of this priority list, there is a great risk that the financial and human resources are spread so thinly that they result in inefficiency and isolated outcomes that miss the opportunity to develop a synergy that would move forward conservation within the heritage sector. We hope that this book, written by the most representative members of this community in Europe, will through its illustration of the benefits of collaboration and the progress that this brings, inspire the reader to action that will contribute to developing international collaboration with other relevant and interested metals heritage groups.
Conservation, corrosion science and evidence-based preservation strategies for metallic heritage artefacts. Relationships between conservation and corrosion scientists are assessed and similarities, differences and synergies identified.
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Corrosion control as a preservation option for heritage metals is advocated as being cost-effective and pragmatic. This will require generation of data to develop predictive conservation and estimation of object lifespan as a function of their intrinsic and extrinsic variables.
Methods for quantitative determination of corrosion rates of chloride infested heritage iron and techniques for scaling to heritage value are discussed. This chapter explores relationships between conservation and corrosion science. There is a general overview of conservation goals and practices when preserving heritage metals and the text explores conservation definitions, structures and goals, as well as thought processes to encourage insight and collaboration. Examples show how corrosion science is knowingly or unknowingly embedded in heritage metals conservation and the chapter discusses its impact on conservation thinking, research and practice.
This acts as an introduction to other contributions to this volume. Corrosion science is embedded in the development, design and assessment of conservation treatments for metallic heritage objects. It indirectly influences preservation strategy and policy, with corrosion control now beginning to be recognised as an acceptable conservation practice [ 1]. The goals, methodologies and principles of corrosion science have been slowly entering conservation practice via an increasing involvement of corrosion and materials scientists in conservation research, with shared interests being identified in conferences as far back as 30 years ago [ 2, 3].
Publication of a previous EFC Green Book centred on heritage also evidences increasing cross-disciplinary interaction  and author profiles within the International Council of Museums ICOM Metals Working Group Triennial conferences have increasingly included corrosion scientists [5—10]. This is significantly influencing conservation thought processes and rationale. The inherent instability of metallic heritage offers similar preservation challenges to those faced in civil engineering and the vehicular and construction industries.
Evolution of museums over the past 50 years has developed their scope to include modern, everyday and high-tech metals in the guise of aircraft, tanks, industrial equipment, space travel vehicles, agricultural machines, washing machines, boats and vehicles. Elsewhere, archaeological museums present specific corrosion problems associated with buried metals and marine museums with chloride-driven corrosion.
Beyond museums are historical monuments that are still in use and must be maintained with the support of engineers and corrosion scientists, preferably with input from conservators to contextualise their repair and upkeep as heritage objects. Clearly, the metals, alloys and contexts of interest to conservators increasingly coincide with those of corrosion scientists.
Each shares the goal of prolonging the survival of metals and both must identify and understand corrosion routes and develop strategies to prevent corrosion. Despite a shared goal, approaches to achieving it may differ. Examining what each can share in terms of research and methodologies can create a synergy to benefit conservation practice and extend the scope of corrosion science research. Defining conservation and the role of conservators is the first step towards identifying common ground between the two professions. Conservators are normally based either in museum contexts or private practice.
Their role is either to select or devise conservation treatments that will preserve heritage metals within specified contexts, then implement these via an action plan.
They are underpinned internationally by a very small group of conservation scientists, who carry out research to build the evidence base required to support the decision-making process for conservation. These few scientists are normally based in large national museums or academic institutions, but their limited numbers and wide remit mean that metals research often constitutes a small part of their work. This contrasts with corrosion science, where the research arm is internationally vast and supported by multinational companies and a large academic presence.
Conservation research is poorly funded and any structure that it has developed is sector driven, often by individuals, within an environment of very limited resources. Its achievements and output, which might be considered modest by corrosion scientists, must be measured within this context, as must its potential development from closer liaison with corrosion science.
This structure means that much conservation research is carried out in isolation and addresses specific problems, rather than forming part of a coordinated national or international research design to answer overarching questions. Grant configurations allow exceptions to exist, such as the successful PROMET study into conservation of metals within the Mediterranean Basin, which involved 26 partner laboratories supported by the 6th European Framework Programme for Technological Research and Development [ 11, 12].
While the publication focus and integrated outcomes of these collaborations confirm that co-ordinated research programmes are the most effective way to address extensive and challenging conservation problems, such projects remain difficult to build and fund. Understandably, the work of most conservation scientists is driven by problems that confront their employers, such as why certain metals corrode in a particular museum showcase or which protective coating performs best for reducing tarnishing of silver.
While these are immediate problems for their employers, thankfully they often have wider application in conservation practice.
Thus, identifying the cause and mechanism for producing black corrosion spots on copper alloys in museum showcases revealed a corrosion route driven by sulphur [ 13]. Outcomes of this study can be extrapolated to other contexts where such corrosion occurs. Similarly, research to assess lacquer performance and longevity as a protective antitarnish coating for a silver dinner service at Apsley House in London  answers a management question for English Heritage, while providing data for use by other conservators choosing lacquers as anti-tarnish coatings.
Developing treatments, modifying them and assessing their success normally lies within the remit of the conservation scientist, but sometimes may be carried out by practising conservators where the demands of a collection require it. A museum tasked with responsibility to preserve large assemblages of unstable archaeological iron will likely donate employee time to addressing this problem, which may involve running or sponsoring research to assess the efficacy of a particular conservation method or its modification to meet the specific context of the corrosion occurring.
Conservators are often responsible for assessing the condition of collections and identifying the causes of corrosion.
The insight this can provide into the success of a treatment is limited, as condition assessments are rarely, if ever, part of a programme originally designed to determine treatment effectiveness from its completion to the point in time where the assessment occurs. It normally comprises a retrospective examination supported by an incomplete evidence base, as recording of object and environment variables is often limited, estimated or non-existent within the period elapsing between treatment completion and condition assessment [ 15].
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