Electrochemical Corrosion Characterization of Submicron WC-12Co Coatings Produced by CGS and HVAF Compared with Sintered Bulks

Núria Cinca, Olivier Lavigne, Riberto Nunes Peres, Conze Susan, Soeren Hoehn, Sergi Dosta, Heli Koivuluoto, Chung Kim, Fernando Santos da Silva, Ville Matikainen, Reza Jafari, Elena Tarrés, Assis Vicente Benedetti

Tutkimustuotos: ArtikkeliScientificvertaisarvioitu

3 Sitaatiot (Scopus)
17 Lataukset (Pure)

Abstrakti

The electrochemical corrosion performance of WC-12 wt% Co in coating and bulk forms has been evaluated in a 3.56 wt% NaCl solution. The coatings were deposited by means of thermal spray techniques, i.e., cold gas spraying (CGS) and high-velocity air fuel (HVAF) spraying, while bulks with different WC sizes were manufactured by conventional pressing and sintering. Microstructural characterizations and phase composition determinations were carried out using scanning electron microscopy and X-ray diffraction. Differences in WC grain size and morphology, carbide dissolution, and cobalt binder phase transformation are discussed according to the inherent characteristics of each processing method. Together with surface roughness (polished/as-sprayed), these features have been observed to directly affect the electrochemical corrosion performance. Electrochemical measurements (open circuit potential, polarization resistance, electrochemical impedance spectroscopy, and polarization curves) showed that the as-sprayed CGS coating presented an electrochemical behavior similar to those of the bulk materials. This was attributed to the higher metallic character of this coating in comparison to that of the HVAF coating. The polished HVAF coating showed anodic activity lower than those of the bulk samples, most likely due to the presence of cobalt–tungsten carbide phases and eventually the lower amount of Co available for dissolution. Finally, the as-sprayed HVAF coating showed very high resistivity due to the presence of surface oxides generated during the deposition process.
AlkuperäiskieliEnglanti
Artikkeli620
JulkaisuCoatings
Vuosikerta12
Numero5
DOI - pysyväislinkit
TilaJulkaistu - toukok. 2022
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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