Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

The impact of chloride desalination on the corrosion rate of archaeological iron

Rimmer, Melanie, Watkinson, David and Wang, Quanyu 2013. The impact of chloride desalination on the corrosion rate of archaeological iron. Studies in Conservation 58 (4) , pp. 326-337. 10.1179/2047058412Y.0000000068

[img]
Preview
PDF - Accepted Post-Print Version
Download (797kB) | Preview

Abstract

Although desalination of archaeological iron reduces its chloride concentration and enhances object stability, the reduction in corrosion rate that this produces has never been quantified. This study measures post-treatment corrosion rates in accelerated corrosion environments to identify the impact of removing chloride ions on corrosion rate. Thirty-five archaeological iron nails, treated individually in either alkaline sulphite or nitrogen-deoxygenated sodium hydroxide, were exposed to 75°C and 75% relative humidity together with 31 untreated objects from the same archaeological sites. Object weight change and visual examination of physical change before and after the test period were used to monitor corrosion. 77% of treated objects showed no weight gain and no visible signs of corrosion, while 90% of untreated objects did corrode. The impact of chloride on corrosion of untreated objects was clearly established by a significant linear correlation between chloride content and weight gain. Treated objects with <400 ppm chloride content showed no corrosion behaviour. Corrosion of treated objects was attributed to incomplete treatment: 93% of objects treated to <5 mg/l Cl− in the final solution bath displayed no corrosion behaviour. Based on these results, desalination of iron objects to enhance their stability offers a valuable option for reducing corrosion rates of archaeological iron, which should increase object lifespan. The results also raise the question of whether low levels of post-treatment residual chloride produce corrosion of any significance. Answering this will be an important step forward for managing the preservation of archaeological iron.

Item Type: Article
Date Type: Publication
Status: Published
Schools: History, Archaeology and Religion
Subjects: Q Science > QD Chemistry
Publisher: Earthscan
ISSN: 0039-3630
Funders: AHRC
Date of First Compliant Deposit: 30 March 2016
Last Modified: 05 Jun 2017 12:40
URI: http://orca.cf.ac.uk/id/eprint/32146

Citation Data

Cited 2 times in Google Scholar. View in Google Scholar

Cited 10 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics