Pollution and Heritage Metals-Effectiveness of Oddy Testing and Mitigation.

Abstract

Metals are particularly sensitive to some pollutant gases. Many museum showcases and store rooms present atmospheres that can corrode cultural heritage artefacts containing metals. Whilst numerous strategies have been reported to mitigate such situations, avoiding them is preferable. Several approaches to testing materials used in construction, fitting out or dressing are used. The relative merits and drawbacks are discussed. Several parameters of the most widely used, accelerated corrosion 'Oddy' test are investigated. The influence of abrasive on subsequent corrosion of lead and copper coupons are assessed. Quantification methods for tested coupons are reviewed. The influence of test duration and temperature are assessed through comparison with real-life, long-term experience of material behaviour. Direct contact tests with touching the test material are investigated. Several materials present in artefacts are known to potentially cause corrosion when enclosed with metals in other artefacts. A number of situations are investigated with pollution and RH and some corrosion rate measurements. Ways to isolate artefacts or mitigate are explored and a decision support model is further developed.