Abstract
In this work, a CoCrFeNiMo high-entropy alloy (HEA) material was prepared by the vacuum arc melting (VAM) method and used for electro-spark deposition (ESD). The purpose of this study was to investigate the phase evolution and microstructure of the CoCrFeNiMo HEA as as-cast and electro-spark-deposited (ESD) coating to assess its suitability for corrosvie environments encountered in geothermal energy production. The composition, morphology, and structure of the bulk material and the coating were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The hardness of the bulk material was measured to access the mechanical properties when preselecting the composition to be pursued for the ESD coating technique. For the same purpose, electrochemical corrosion tests were performed in a 3.5 wt.% NaCl solution on the bulk material. The results showed the VAM CoCrFeNiMo HEA material had high hardness (593 HV) and low corrosion rates (0.0072 mm/year), which is promising for the high wear and corrosion resistance needed in the harsh geothermal environment. The results from the phase evolution, chemical composition, and microstructural analysis showed an adherent and dense coating with the ESD technique, but with some variance in the distribution of elements in the coating. The crystal structure of the as-cast electrode CoCrFeNiMo material was identified as face centered cubic with XRD, but additional BCC and potentially σ phase was formed for the CoCrFeNiMo coating.
| Original language | English |
|---|---|
| Article number | 406 |
| Journal | Coatings |
| Volume | 9 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 1 Jun 2019 |
| Externally published | Yes |
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Keywords
- Coating
- Corrosion
- Electro-spark deposition
- Geothermal environment
- High-entropy alloy
- Microstructure
- XRD
ASJC Scopus subject areas
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry
Cite this
Phase evolution and microstructure analysis of CoCrFeNiMo high-entropy alloy for electro-spark-deposited coatings for geothermal environment. / Karlsdottir, Sigrun N.; Geambazu, Laura E.; Csaki, Ioana; Thorhallsson, Andri I.; Stefanoiu, Radu; Magnus, Fridrik; Cotrut, Cosmin.
In: Coatings, Vol. 9, No. 6, 406, 01.06.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phase evolution and microstructure analysis of CoCrFeNiMo high-entropy alloy for electro-spark-deposited coatings for geothermal environment
AU - Karlsdottir, Sigrun N.
AU - Geambazu, Laura E.
AU - Csaki, Ioana
AU - Thorhallsson, Andri I.
AU - Stefanoiu, Radu
AU - Magnus, Fridrik
AU - Cotrut, Cosmin
PY - 2019/6/1
Y1 - 2019/6/1
N2 - In this work, a CoCrFeNiMo high-entropy alloy (HEA) material was prepared by the vacuum arc melting (VAM) method and used for electro-spark deposition (ESD). The purpose of this study was to investigate the phase evolution and microstructure of the CoCrFeNiMo HEA as as-cast and electro-spark-deposited (ESD) coating to assess its suitability for corrosvie environments encountered in geothermal energy production. The composition, morphology, and structure of the bulk material and the coating were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The hardness of the bulk material was measured to access the mechanical properties when preselecting the composition to be pursued for the ESD coating technique. For the same purpose, electrochemical corrosion tests were performed in a 3.5 wt.% NaCl solution on the bulk material. The results showed the VAM CoCrFeNiMo HEA material had high hardness (593 HV) and low corrosion rates (0.0072 mm/year), which is promising for the high wear and corrosion resistance needed in the harsh geothermal environment. The results from the phase evolution, chemical composition, and microstructural analysis showed an adherent and dense coating with the ESD technique, but with some variance in the distribution of elements in the coating. The crystal structure of the as-cast electrode CoCrFeNiMo material was identified as face centered cubic with XRD, but additional BCC and potentially σ phase was formed for the CoCrFeNiMo coating.
AB - In this work, a CoCrFeNiMo high-entropy alloy (HEA) material was prepared by the vacuum arc melting (VAM) method and used for electro-spark deposition (ESD). The purpose of this study was to investigate the phase evolution and microstructure of the CoCrFeNiMo HEA as as-cast and electro-spark-deposited (ESD) coating to assess its suitability for corrosvie environments encountered in geothermal energy production. The composition, morphology, and structure of the bulk material and the coating were analyzed using scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The hardness of the bulk material was measured to access the mechanical properties when preselecting the composition to be pursued for the ESD coating technique. For the same purpose, electrochemical corrosion tests were performed in a 3.5 wt.% NaCl solution on the bulk material. The results showed the VAM CoCrFeNiMo HEA material had high hardness (593 HV) and low corrosion rates (0.0072 mm/year), which is promising for the high wear and corrosion resistance needed in the harsh geothermal environment. The results from the phase evolution, chemical composition, and microstructural analysis showed an adherent and dense coating with the ESD technique, but with some variance in the distribution of elements in the coating. The crystal structure of the as-cast electrode CoCrFeNiMo material was identified as face centered cubic with XRD, but additional BCC and potentially σ phase was formed for the CoCrFeNiMo coating.
KW - Coating
KW - Corrosion
KW - Electro-spark deposition
KW - Geothermal environment
KW - High-entropy alloy
KW - Microstructure
KW - XRD
UR - http://www.scopus.com/inward/record.url?scp=85069794279&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85069794279&partnerID=8YFLogxK
U2 - 10.3390/COATINGS9060406
DO - 10.3390/COATINGS9060406
M3 - Article
AN - SCOPUS:85069794279
VL - 9
JO - Coatings
JF - Coatings
SN - 2079-6412
IS - 6
M1 - 406
ER -