Assessing of New Coatings for Iron Artifacts Conservation by Recurrence Plots Analysis

Paola Roncagliolo Barrera,Francisco Rodríguez Gómez,Esteban García Ochoa

doi:10.3390/coatings9010012

Paola Roncagliolo Barrera, Francisco Rodríguez Gómez + Show 1 more

Open Access

https://doi.org/10.3390/coatings9010012

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Abstract

Cast iron has stood for centuries of invention. It is a very versatile and durable material. Coating systems are a low-maintenance protection method. The purpose of this research is to increase the Paraloid coating’s resistance when applied to iron in high humidity atmospheres, with the addition of caffeine (1,3,7-dimethylxanthine) and nicotine (S)-3-(1-methylpyrrolidin-2-yl) pyridine as corrosion inhibitors; the resistance of protection versus exposure time will be evaluated by using electrochemical noise. A statistical analysis of the electrochemical noise signals was carried out. Recurrence plots were used as a powerful tool in the analysis to complement the data obtained and they predicted the evaluation of coatings behaviors performance versus time. The outcomes show that the addition of inhibitors increases and improves the performance as a temporary protection of Paraloid and that protection in high relative humidity was improved. Recurrence plots and parameter quantification show the variances in the surface corrosion dynamics.

Highlights

Temporary protection systems based on coatings are usually used in iron objects preserved in museums
The comparative analyses of the electrochemical noise signals obtained from a series of potential or current in function of the acquisition time are shown below
Changes are observed in the fluctuations in both signals obtained as a function of the increase in relative humidity, as a consequence of increasing the thickness of the water film and the interaction present in the microcells becomes more intense

Summary

Introduction

Temporary protection systems based on coatings are usually used in iron objects preserved in museums. The protective layer insulates metal surfaces from moisture, air pollutants, acids, etc. This method provides a passive protection against corrosion [1]. Its original solvent is soluble for more than 200 years (according to a projection based on accelerated aging studies). It is a fairly stable resin, its polymer chains deteriorate quickly if exposed to ultraviolet radiation, and its high water permeability decreases its useful life, which is well-known in the industrial field [3]

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