I recently read a short paper on
bronze disease: Corrosion Risk Assessment Approach in Archaeological Bronze
Collections: From Burial to Long-term Preservation Environments, by Iranian professor Omid Oudbashi.
https://www.academia.edu/28911095/Corrosion_Risk_Assessment_Approach_in_Archaeological_Bronze_Collections_From_Burial_to_Long-term_Preservation_EnvironmentsThe findings are very interesting and confirm much of what we already believe.
First, the chloride content of the soil is critical.
Bronze objects that come from a high chloride content soil are in effect already doomed. A chloride content of less than 10mg/kg of soil is ideal as items are safe even in a wet environment. A content of 10-100 mg/kg is ok in dry and semi-dry environments but is bad in more humid environments. Higher chloride content is bad. Above 1000mg/kg is very bad.
Second, the humidity of the modern storage environment is critical. At less than 40% humidity even high risk objects should be safe from deterioration. The 40-55% humidity zone is bad as that allows for the
bronze disease reaction to begin or continue. Over 55% humidity is really bad....
Invest in those de-humidifiers.
SC