scholarly journals Non-Invasive Assessment of PVA-Borax Hydrogel Effectiveness in Removing Metal Corrosion Products on Stones by Portable NMR

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 265
Author(s):  
Valeria Stagno ◽  
Alessandro Ciccola ◽  
Roberta Curini ◽  
Paolo Postorino ◽  
Gabriele Favero ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Relaxation Times ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Stone Surface ◽  
Carrara Marble ◽  
Stone Materials ◽  
Before And After ◽  
Boron Ions ◽  
Portable Nmr

The cleaning of buildings, statues, and artworks composed of stone materials from metal corrosion is an important topic in the cultural heritage field. In this work the cleaning effectiveness of a PVA-PEO-borax hydrogel in removing metal corrosion products from different porosity stones has been assessed by using a multidisciplinary and non-destructive approach based on relaxation times measurement by single-sided portable Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy—Energy Dispersive Spectroscopy (SEM-EDS), and Raman Spectroscopy. To this end, samples of two lithotypes, Travertine and Carrara marble, have been soiled by triggering acidic corrosion of some copper coins in contact with the stone surface. Then, a PVA-PEO-borax hydrogel was used to clean the stone surface. NMR data were collected in untreated, soiled with corrosion products, and hydrogel-cleaned samples. Raman spectroscopy was performed on PVA-PEO-borax hydrogel before and after cleaning of metal corrosion. Furthermore, the characterization of the dirty gel was obtained by SEM-EDS. The combination of NMR, SEM-EDS and Raman results suggests that the mechanism behind the hydrogel cleaning action is to trap heavy metal corrosion products, such as Cu2+ between adjacent boron ions cross-linked with PVA. Moreover, the PVA-PEO-borax hydrogel cleaning effectiveness depends on the stone porosity, being better in Carrara marble compared to Travertine.

scholarly journals The formation of formates: 3a review of metal formates on heritage objects

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Gerhard Eggert ◽  
Andrea Fischer
Keyword(s):  
Degradation Products ◽  
Dominant Role ◽  
Copper Alloys ◽  
Wood Products ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Irreversible Damage ◽  
Preventive Conservation ◽  
Calcium Formate ◽  
Metal Formates

AbstractMetal formates sometimes occur as degradation products on heritage objects due to the use of wood products or other sources of formic acid and formaldehyde. They are often related to alkaline surfaces which transform formaldehyde directly into formate. The dominant role of formate on alkaline surfaces, for example in glass-induced metal corrosion (GIM) or calcium carbonate degradation, was explored in the Stuttgart research on rare heritage corrosion products. This review discusses these findings together with those from the literature: ocurrences of sodium and potassium formate on glass, calcium formate and calcium acetate-formate phases on calcareous materials, magnesium formate on Sorel cement and dolomitic sandstone, lead formate on metal and pigments, cadmium formate on coated objects, as well as various copper and zinc formates on copper alloys. In the latter cases, formates dominate as glass-induced metal corrosion products. The formation of formates constitutes irreversible damage, degrading the material of heritage objects. Therefore, preventive conservation needs to remove all sources of carbonyl pollutants in order to avoid such corrosion.

scholarly journals Remedial Treatment of Corroded Iron Objects by EnvironmentalAeromonasIsolates

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Wafa M. Kooli ◽  
Thomas Junier ◽  
Migun Shakya ◽  
Mathilde Monachon ◽  
Karen W. Davenport ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Building Materials ◽  
Solid Phase ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Economic Losses ◽  
Cytotoxic Activities ◽  
Iron Corrosion ◽  
Pathogenic Potential ◽  
Wide Range

ABSTRACTUsing bacteria to transform reactive corrosion products into stable compounds represents an alternative to traditional methods employed in iron conservation. Two environmentalAeromonasstrains (CA23 and CU5) were used to transform ferric iron corrosion products (goethite and lepidocrocite) into stable ferrous iron-bearing minerals (vivianite and siderite). A genomic and transcriptomic approach was used to analyze the metabolic traits of these strains and to evaluate their pathogenic potential. Although genes involved in solid-phase iron reduction were identified, key genes present in other environmental iron-reducing species are missing from the genome of CU5. Several pathogenicity factors were identified in the genomes of both strains, but none of these was expressed under iron reduction conditions. Additionalin vivotests showed hemolytic and cytotoxic activities for strain CA23 but not for strain CU5. Both strains were easily inactivated using ethanol and heat. Nonetheless, given a lesser potential for a pathogenic lifestyle, CU5 is the most promising candidate for the development of a bio-based iron conservation method stabilizing iron corrosion. Based on all the results, a prototype treatment was established using archaeological items. On those, the conversion of reactive corrosion products and the formation of a homogenous layer of biogenic iron minerals were achieved. This study shows how naturally occurring microorganisms and their metabolic capabilities can be used to develop bio-inspired solutions to the problem of metal corrosion.IMPORTANCEMicrobiology can greatly help in the quest for a sustainable solution to the problem of iron corrosion, which causes important economic losses in a wide range of fields, including the protection of cultural heritage and building materials. Using bacteria to transform reactive and unstable corrosion products into more-stable compounds represents a promising approach. The overall aim of this study was to develop a method for the conservation and restoration of corroded iron items, starting from the isolation of iron-reducing bacteria from natural environments. This resulted in the identification of a suitable candidate (Aeromonassp. strain CU5) that mediates the formation of desirable minerals at the surfaces of the objects. This led to the proof of concept of an application method on real objects.

scholarly journals Raman investigation of corrosion products on Roman copper-based artefacts

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 129
Author(s):  
Leila Es Sebar ◽  
Leonardo Iannucci ◽  
Yuval Goren ◽  
Peter Fabian ◽  
Emma Angelini ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Roman Period ◽  
Corrosion Products ◽  
Beer Sheva ◽  
Chemometric Technique ◽  
Components Analysis ◽  
Main Components

<p class="Abstract">This paper illustrates a case study related to the characterisation of corrosion products present on recently excavated artefacts. The archaeological findings, from the Rakafot 54 site (Beer-Sheva, Israel), consist of 23 coins and a pendant, all dating back to the Roman period. Raman spectroscopy was used to identify the corrosion products that compose the patina covering the objects. To facilitate and support their identification, spectra were then processed using principal components analysis. This chemometric technique allowed the identification of two main compounds, classified as atacamite and clinoatacamite, which formed the main components of the patinas. The results of this investigation can help in assessing the conservation state of artefacts and defining the correct restoration strategy.</p>

scholarly journals Study of the Behavior of Structural Materials Treated with Bioconsolidant

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5369
Author(s):  
Yolanda Spairani ◽  
Arianna Cisternino ◽  
Dora Foti ◽  
Michela Lerna ◽  
Salvador Ivorra
Keyword(s):  
Structural Materials ◽  
Mechanical Tests ◽  
Existing Building ◽  
Experimental Campaign ◽  
Stone Materials ◽  
Before And After ◽  
Optical Photomicrograph ◽  
Stone Material ◽  
Artificial Stone ◽  
Non Destructive

In this article, the effectiveness of the bioconsolidation technique applied to degraded structural materials is illustrated as a new method of consolidation and conservation of the existing building heritage in a less invasive way. Satisfactory results have been obtained by an experimental campaign carried out through non-destructive diagnostic tests, static destructive mechanical tests, and microstructural analyses on a series of natural stone material specimens and artificial stone materials before and after the use of bioconsolidants. The consolidated specimens have been tested after three to four weeks after the application of the M3P nutritional solution on each specimen. The effect on the microstructure of this technique has also been observed using scanning electron microscope and optical photomicrograph, the formation of new calcium carbonate crystals promoting the structural consolidation of the materials under examination was observed in all the specimens analyzed.

In situ Raman spectroscopy study of corrosion products on the surface of carbon steel in solution containing Cl− and

2011 ◽  
Vol 18 (8) ◽  
pp. 1981-1989 ◽  
Author(s):  
Xin Zhang ◽  
Kui Xiao ◽  
Chaofang Dong ◽  
Junsheng Wu ◽  
Xiaogang Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Carbon Steel ◽  
Corrosion Products ◽  
Spectroscopy Study ◽  
In Situ Raman Spectroscopy ◽  
In Situ Raman

X-Ray Spectrographic Analysis of the 3-d Transition Metal Corrosion Products Using Potassium Bromide Disks*

1963 ◽  
Vol 7 ◽  
pp. 590-597
Author(s):  
L. A. Schluter
Keyword(s):  
Pulse Height ◽  
Weight Ratio ◽  
Internal Standard ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Small Samples ◽  
Bragg Angle ◽  
X Ray ◽  
Calibration Curves ◽  
Intensity Ratios

AbstractA technique has been developed for quantitative analysis of the major constituents in small samples (less than 0.1 g) of corrosion products found On various missile parts. The technique was developed primarily to aid in interpretation of X-ray diffraction patterns of multicomponent corrosion products. The corrosion sample is mixed with KBr and the mixture is pressed into a disk in the same fashion commonly used in infrared work. The Br Kβ1 line serves as an internal standard. Intensities of the element's Kα line and the internal standard are established by scanning through the appropriate Bragg angle and recording peak heights on a strip-chart recorder. A xenon-filled proportional detector and a pulse-height analyzer were used.The percent of an element is determined by references to calibration curves which relate intensity ratios to weight ratios for the 3-d transition metals. The oxides of the metals were used in the preparation of the calibration curves. The weight ratio vs. intensity ratio relationship is linear over the weight ratio range 0.01 to 0.11. Data were collected using an air path and a helium path; the higher intensity ratios obtained with, the helium path, and the dependence of intensity on atomic number are illustrated. A comparison is made between the intensity ratios in a KBr matrix and in a NaBr matrix. The technique developed requires about 15 min sample preparation time.

Dechlorination of large marine iron artifact using a novel technique involving impressed current

2015 ◽  
Vol 62 (4) ◽  
pp. 259-269
Author(s):  
Georgios Batis ◽  
Angeliki Zacharopoulou ◽  
Evgenia Zacharopoulou ◽  
Helene Siova ◽  
Vasilike Argyropoulos
Keyword(s):  
Organic Coating ◽  
Corrosion Products ◽  
Alkaline Solutions ◽  
Content Type ◽  
Conservation Treatment ◽  
Chemical Reagents ◽  
Before And After ◽  
Long Time ◽  
Electrochemical Chloride Extraction ◽  
Short Time

Purpose – This paper aims to develop an electrochemical dechlorination method for large objects in a short time, which were for a long time in the sea. Traditionally, in conservation, chlorides are extracted from marine iron artifacts using complete immersion of those objects in alkaline solutions with or without electrolysis. However, these techniques are time-consuming and very costly, especially when applied to large marine artifacts such as cannons and anchors. Design/methodology/approach – An appropriate sponge was chosen based on resistance to NaOH and the rate of exacted chlorides. Application of electrochemical dechlorination in situ and removal of chloride were measured by the scanning electron microscope (SEM)-EDAX method on the corrosion products and by titration of the electrolysis solution. X-ray diffraction (XRD) method is used for identification of corrosion products before and after application of electrochemical chloride extraction. Findings – The electrochemical chloride extraction (ECE) method is applied against the corrosion of reinforced concrete. From the authors’ research, it is obvious that ECE can successfully extract chlorides from dried large metallic objects exported from the sea. The method of ECE removes the majority of chlorides from the metal during conservation treatment so that the application of organic coating will allow the object to remain stable over a long period. Originality/value – A new methodology was developed for dechlorination of metallic objects exported from the sea in a short time and thus the consumption of chemical reagents was cut down.

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