Plasma-sprayed chromia coatings are known to have excellent corrosion and wear properties in highly acidic conditions at ambient and elevated temperatures, but are not watertight due to their intrinsic porosity. Therefore, in applications involving aggressive environments, the whole component is usually made of a corrosion-resistant alloy, to which the Cr2O3 coating imparts the necessary wear resistance. However, in such aggressive environments, the survival of thermal spray metallic bond layers becomes an issue. The present study deals with the performance in sulfuric acid solutions of coated systems consisting of a Hastelloy C-276 substrate and a plasma-sprayed Cr2O3 top coating with four different intermediate bond coatings. The bond coatings were HVOF-sprayed Ni-20Cr, Hastelloy C-276 and Ultimet alloys and plasma-sprayed tantalum. Open-circuit measurement, electrochemical polarization and electrochemical impedance spectroscopy tests were carried out at room temperature (RT) in solutions with various concentrations. Also, static immersion tests were performed at RT and 60 °C. The results revealed that the HVOF-sprayed Ni-20Cr and Ultimet alloy coatings were significantly attacked by the sulfuric acid electrolyte, especially at 60 °C, whereas the HVOF-sprayed Hastelloy C-276 and plasma-sprayed Ta coatings performed significantly better.

Corrosion Properties of Thermally Sprayed Bond Coatings Under Plasma-Sprayed Chromia Coating in Sulfuric Acid Solutions / Bolelli, G.; Meschini, D.; Varis, T.; Testa, V.; Morelli, S.; Lusvarghi, L.; Vuoristo, P.. - In: JOURNAL OF THERMAL SPRAY TECHNOLOGY. - ISSN 1059-9630. - 29:1-2(2020), pp. 270-284. [10.1007/s11666-019-00922-9]

Corrosion Properties of Thermally Sprayed Bond Coatings Under Plasma-Sprayed Chromia Coating in Sulfuric Acid Solutions

Bolelli G.;Meschini D.;Testa V.;Morelli S.;Lusvarghi L.;
2020-01-01

Abstract

Plasma-sprayed chromia coatings are known to have excellent corrosion and wear properties in highly acidic conditions at ambient and elevated temperatures, but are not watertight due to their intrinsic porosity. Therefore, in applications involving aggressive environments, the whole component is usually made of a corrosion-resistant alloy, to which the Cr2O3 coating imparts the necessary wear resistance. However, in such aggressive environments, the survival of thermal spray metallic bond layers becomes an issue. The present study deals with the performance in sulfuric acid solutions of coated systems consisting of a Hastelloy C-276 substrate and a plasma-sprayed Cr2O3 top coating with four different intermediate bond coatings. The bond coatings were HVOF-sprayed Ni-20Cr, Hastelloy C-276 and Ultimet alloys and plasma-sprayed tantalum. Open-circuit measurement, electrochemical polarization and electrochemical impedance spectroscopy tests were carried out at room temperature (RT) in solutions with various concentrations. Also, static immersion tests were performed at RT and 60 °C. The results revealed that the HVOF-sprayed Ni-20Cr and Ultimet alloy coatings were significantly attacked by the sulfuric acid electrolyte, especially at 60 °C, whereas the HVOF-sprayed Hastelloy C-276 and plasma-sprayed Ta coatings performed significantly better.
25-set-2019
29
1-2
270
284
Corrosion Properties of Thermally Sprayed Bond Coatings Under Plasma-Sprayed Chromia Coating in Sulfuric Acid Solutions / Bolelli, G.; Meschini, D.; Varis, T.; Testa, V.; Morelli, S.; Lusvarghi, L.; Vuoristo, P.. - In: JOURNAL OF THERMAL SPRAY TECHNOLOGY. - ISSN 1059-9630. - 29:1-2(2020), pp. 270-284. [10.1007/s11666-019-00922-9]
Bolelli, G.; Meschini, D.; Varis, T.; Testa, V.; Morelli, S.; Lusvarghi, L.; Vuoristo, P.
File in questo prodotto:
File Dimensione Formato  
Bolelli2020_Article_CorrosionPropertiesOfThermally (1).pdf

non disponibili

Tipologia: Versione pubblicata dall'editore
Dimensione 2.45 MB
Formato Adobe PDF
2.45 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1188389
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 3
social impact