“Gold corrosion”: An alternative source of red stains on gold coins

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388980%3A_____%2F21%3A00540290" target="_blank" >RIV/61388980:_____/21:00540290 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216305:26620/21:PU140493 RIV/61989592:15310/21:73609498 RIV/62156489:43210/21:43919332

Výsledek na webu

<a href="https://doi.org/10.1016/j.mtla.2021.101025" target="_blank" >https://doi.org/10.1016/j.mtla.2021.101025</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.mtla.2021.101025" target="_blank" >10.1016/j.mtla.2021.101025</a>

Jazyk výsledku

angličtina

Název v původním jazyce

“Gold corrosion”: An alternative source of red stains on gold coins

Popis výsledku v původním jazyce

Recently, the phenomena of red stains defects was found on historical and modern golden coins around the world. This “Gold corrosion” can be the reason for reduction of coin value, especially of modern high-premium coins. In such modern investment coins, the contamination of the surface by microscopic particles of metallic silver is reported to be a common cause of such stains. Corrosion of these particles (or even back reduction) is associated with a distinct change of colour. In the case of historical coins, this relatively simple explanation does not respond in some cases. The submitted study is dealing with analysis of red stains on of Austro-Hungarian gold ten crowns coins, which served as a common part of circulating currency. They were therefore minted in thousands/million pieces by standard procedures each year. It is therefore quite logical that these coins can have different mechanisms of red spots formation than modern high-premium coins. Red stains on Austro-Hungarian coins were analysed by the means of light (LM) and digital microscopy (DM), energy-dispersive X-ray spectroscopy (EDS), energy dispersive X-ray fluorescence spectroscopy (XRF), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Mössbauer spectroscopy, X-ray powder micro-diffraction (µ-XRPD) and Raman microscopy. The EDS, XRF and XPS analysis points to the presence of iron and oxygen in red stains, no silver or its corrosion products were detected. The exact determination of red stains was done by µ-XRPD and Raman microscopy where an iron(III) oxide-hydroxide (Goethite) was found as main product.

Název v anglickém jazyce

“Gold corrosion”: An alternative source of red stains on gold coins

Popis výsledku anglicky

Recently, the phenomena of red stains defects was found on historical and modern golden coins around the world. This “Gold corrosion” can be the reason for reduction of coin value, especially of modern high-premium coins. In such modern investment coins, the contamination of the surface by microscopic particles of metallic silver is reported to be a common cause of such stains. Corrosion of these particles (or even back reduction) is associated with a distinct change of colour. In the case of historical coins, this relatively simple explanation does not respond in some cases. The submitted study is dealing with analysis of red stains on of Austro-Hungarian gold ten crowns coins, which served as a common part of circulating currency. They were therefore minted in thousands/million pieces by standard procedures each year. It is therefore quite logical that these coins can have different mechanisms of red spots formation than modern high-premium coins. Red stains on Austro-Hungarian coins were analysed by the means of light (LM) and digital microscopy (DM), energy-dispersive X-ray spectroscopy (EDS), energy dispersive X-ray fluorescence spectroscopy (XRF), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Mössbauer spectroscopy, X-ray powder micro-diffraction (µ-XRPD) and Raman microscopy. The EDS, XRF and XPS analysis points to the presence of iron and oxygen in red stains, no silver or its corrosion products were detected. The exact determination of red stains was done by µ-XRPD and Raman microscopy where an iron(III) oxide-hydroxide (Goethite) was found as main product.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Materialia

ISSN

2589-1529

e-ISSN

—

Svazek periodika

15

Číslo periodika v rámci svazku

MAR

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

8

Strana od-do

101025

Kód UT WoS článku

000634687500008

EID výsledku v databázi Scopus

2-s2.0-85100685911