The Subcritical Mass-Treatment of a Range of Iron Artifacts from Varying Contexts

Dublin Core

Title

The Subcritical Mass-Treatment of a Range of Iron Artifacts from Varying Contexts

Subject

Session 7
Preservation and conservation of wet archaeological materials and site management

Description

The use of subcritical fluids for the treatment of archaeological and marine archaeological iron artifacts has been under experimentation at the Clemson University’s Warren Lasch Conservation Center (WLCC) since 2003 and has shown promise of providing solutions to some of the issues related to the more traditional desalination treatments: Treatment times are but a fraction of those required by the soaking methods; chloride readings are brought to near-negligible levels; desalination can be carried out with or without prior deconcretion; solutions are maintained in sealed containers for the duration of the treatments; and positive results have been seen so far with tests for long-term stability of treated artifacts. Particularly remarkable has been the effect the process appears to have had on corrosion matrices containing the chloride-hosting iron oxyhydroxide, Akagenéite (β-FeOOH) on artifacts that have been allowed to dry out. Results have shown a significant reduction in the quantities of this phase – often linked to the continuation of active corrosion processes within iron artifacts – through transformation into more stable corrosion products such as magnetite and hematite. Experiments carried out to date have not only involved single samples and artifacts, but testing has progressed to a stage where numerous artifacts have been successfully stabilized simultaneously in the same batch. The work presented describes three of such desalination treatments. The first run included a single wrought iron ballast block from the H.L. Hunley, a confederate Civil War submarine lost in battle in 1864. This was followed by the first batch run on five similar ballast blocks and a second with nine iron artifacts of varying composition, context and condition, selected from the National Park Service (NPS - USA) curatorial collection.

Creator

Nasanen, L. M. E.
González-Pereyra, N. G.
Cretté, S.A.

Date

November 2011

Files

Citation

Nasanen, L. M. E., González-Pereyra, N. G., and Cretté, S.A., “The Subcritical Mass-Treatment of a Range of Iron Artifacts from Varying Contexts,” The MUA Collection, accessed December 14, 2017, http://www.themua.org/collections/items/show/1255.

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