Evolution of patinas on copper exposed in a suburban area

Watanabe, Masamitsu; Toyoda, E.; Handa, Tomohiro; Ichino, Toshihiro; Kuwaki, Nobuo; Higashi, Youichirou; Tanaka, Tohru

doi:10.1016/j.corsci.2006.05.044

Cited by 31 publications

(41 citation statements)

References 27 publications

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“…As shown in Table 1, the average relative humidity outdoors was much higher than the average relative humidity indoors, so cuprite formation was enhanced in the presence of thick surface electrolyte. Interestingly, two kinds of basic copper sulphate [posnjakite (Cu 4 SO 4 (OH) 6 6 ] were found on the copper exposed outdoors in addition to the cuprite and chalcocite. In the early stage of copper patination in urban, rural/ coastal, suburban and volcanic areas, posnjakite, in addition to cuprite, forms on copper.…”

Section: Resultsmentioning

confidence: 99%

“…Several researchers 3,26 have attributed the formation mechanism of basic copper sulphates such as posnjakite to a dissolution-precipitation reaction. For posnjakite formation, the following mechanism was proposed by Lobnig et al 26 4Cu 2z z6OH { zSO 2{ 4 zH 2 O?Cu 4 SO 4 (OH) 6 :…”

Section: Resultsmentioning

confidence: 99%

“…1,2,6 The formation mechanism of brochantite is also a dissolution-precipitation reaction. There are three possible origins for the sulphate ions that formed basic copper sulphates.…”

Section: Resultsmentioning

confidence: 99%

“…The crystalline corrosion products found on the plate exposed indoors were chalcocite (Cu 2 S) and cuprite (Cu 2 O), and the former was predominant. Those that formed on the one exposed outdoors were chalcocite, cuprite, posnjakite [Cu 4 SO 4 (OH) 6 .H 2 O] and brochantite [Cu 4 SO 4 (OH) 6 ]. Surface chemical state analysis by XPS showed that there were differences in the shapes of the Cu 2p and Cu LMM Auger spectra between the two plates.…”

Section: Discussionmentioning

confidence: 99%

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Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations

Watanabe

Takaya

Handa

et al. 2013

Corrosion Engineering, Science and Technology

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Corrosion products formed on copper exposed indoors and outdoors at sites with high hydrogen sulphide (H 2 S) concentrations were characterised using several analytical techniques. The crystalline corrosion products that formed on the copper exposed indoors were chalcocite (Cu 2 S) and cuprite (Cu 2 O), while those that formed on the copper exposed outdoors were chalcocite, cuprite and basic copper sulphates. Surface analysis by X-ray photoelectron spectroscopy revealed differences between the copper exposed indoors and outdoors that are explained by the composition, localisation and oxidation of the corrosion products. The surface morphologies of the corrosion products also differed. Elemental depth profiling by glow discharge optical emission spectroscopy revealed that the corrosion products that formed indoors were mainly chalcocite with cuprite only at and near the surface. In contrast, the corrosion products that formed outdoors were a mixture of chalcocite and cuprite. These differences in corrosion products are attributed to the differences in relative humidity during exposure.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…1,2,6 The formation mechanism of brochantite is also a dissolution-precipitation reaction. There are three possible origins for the sulphate ions that formed basic copper sulphates.…”

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations

Watanabe

Takaya

Handa

et al. 2013

Corrosion Engineering, Science and Technology

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“…Dlhodobá atmosférická expozícia vedie k nerovnomerným koróznym procesom [72]. Pochopenie tohto typu korózie je pre meď a jej zliatiny, najmä bronz veľmi dôležitá, pretože táto zliatina je široko využívaná na vý-robu materiálov, ktoré sú trvalo vystavené vonkajšej atmosfére, ako napríklad v kovových artefaktoch [9,73].…”

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Copper and copper patina

Rak

Bureš

2017

Koroze a Ochrana Materialu

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konektory), ale použitie v iných oblastiach je možné (napr. dekorácie, sochy). Na nechránenej medi sa veľmi rýchlo objavuje čierna vrstvička kupritu Cu 2 O [1]. V priebehu niekoľkých rokov je tento povlak nahradený charakteristickou zelenomodrou vrstvičkou [2, 3]. Toto sfarbenie na bronze alebo iných kovoch je označované ako "patina" [1]. Medené patiny sú priestorovo heterogénne vrstvy, ktoré obsahujú prázdne priestory a dtiny. Pórovitosť môže byť ľahko dokázaná schopnosťou patiny absorbovať veľké množstvo vody [4]. Zlúčeniny patiny sú vytvárané chemickou reakciou medi so stopovými prvkami z atmosféry najmä síranmi a chloridmi [5]. Medená patina väčšinou pozostáva z dvoch odlišných vrstiev, 5-10 µm vrstvy kontinuálnej vrstvy kupritu (Cu 2 O) chrániacej základný materiál a vrchnej pórovitej vrstvy 5-40 µm tvorenej zásaditým síranom meďnatým nazývaným aj brochantit (Cu 4 SO 4 (OH) 6 ) alebo bázického chloridu meďnatého atakamitu (Cu 2 Cl(OH) 3 ). Brochantit sa vyskytuje bežnejšie ako atakamit keďže ten sa vytvára iba v prímorských oblastiach [4].Rozpúšťanie medi má nasledujúci mechanizmus: [2, 6]. Príprava umelej patiny na medi a jej zliatinách bola študovaná veľmi dlho, v súčasnosti existujú postupy pre jej prípravu [7][8][9]. V dnešnej dobe väčšina chemických analýz takýchto artefaktov, analýza koróznych procesov a kolorimetrické analýzy sa robia kvôli určeniu pravosti a pôvodu bronzovej zliatiny [9][10][11][12][13][14][15]. Medzi techniky používané na charakterizáciu patín patria skenovacia elektrónová mikroskopia (SEM) s energiovo disperznou spektroskopiou (EDS), elektrochemická impedančná spektroskopia (EIS) a infračervená spektroskopia s Fourierovou transformáciou (FTIR) [16, 17]

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Raman investigation of artificial patinas on recent bronze – Part I: climatic chamber exposure

Ropret

Kosec

2012

J Raman Spectroscopy

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In humid air, copper and its high copper alloys (bronze) tend to form an oxide layer (patina). Natural patinas protect copper and its alloys from further corrosion processes. On the other hand, artists have frequently deliberately patinated bronze for visual effects. Thus, it is of great importance to study the patina changing mechanism to follow its chemical changes and to predict in advance the likely corrosion processes. Green chloride and green nitrate patinas, applied over the brown artist's patina, were tested, and also brown patina and the patina that develops on bare bronze. The Raman spectra were studied after chemical patination, and after exposing the patina samples in a climatic chamber, which can produce an environment that resembles an industrial atmosphere, for 12 weeks. The structures of the patinas and of the corrosion products were characterized by scanning electron microscopy, Raman spectroscopy and X-ray diffraction. Cuprite and cuprous sulfite were found on the brown patina, atacamite on the green chloride patina, and a mixture of gerhardite and rouaite on the blue to green nitrate type patina. After 12 weeks of exposure to humidity, a controlled concentration of SO 2 , and salt spray mist, the corrosion products changed. In general, clinoatacamite and paratacamite are the end corrosion products, after an intermediate brochantite stage on the green chloride and green nitrate type patinas. The end products of each patina type are given.

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Evolution of patinas on copper exposed in a suburban area

Cited by 31 publications

References 27 publications

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations

Copper and copper patina

Raman investigation of artificial patinas on recent bronze – Part I: climatic chamber exposure

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Evolution of patinas on copper exposed in a suburban area

Cited by 31 publications

References 27 publications

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H2S concentrations

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H2S concentrations

Copper and copper patina

Raman investigation of artificial patinas on recent bronze – Part I: climatic chamber exposure

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Product

Resources

About

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations

Characterisation of corrosion products formed on copper exposed at indoor and outdoor sites with high H₂S concentrations