Corrosion and wear resistant Cr₄₀Co₄₀Ni₂₀ coatings produced by plasma transferred arc

Author(s)

Rodrigues, L. C. M. ; Koga, G. Y. ; Coury, F. G. ; Bolfarini, C. ; Kiminami, C. S. ; Cardozo, E. P. ; d'Oliveira, A. S. C. M. ; Botta, W. J.

• Document type: Journal article
• Source: SURFACE & COATINGS TECHNOLOGY; v. 496, p. 15-pg., 2024-12-26.

Abstract

Gas atomized Cr40Co40Ni20 multi-principal element alloy (MPEA), size ranging from 106 to 180 mu m, was used as feedstock to coat carbon steel substrates by Plasma Transferred Arc (PTA) process. The processing conditions studied were: i) arc current [100, 120 and 180 A] and, ii) powder feeding rate [6 and 10 g/min]. The coatings were characterized by X-ray diffraction (XRD), optical (OM), confocal (CM), scanning (SEM) and transmission (TEM) electron microscopy. Vickers microhardness was measured on the top and cross section of the polished coatings. Tribological properties were assessed using a reciprocal pin-on-plate set-up while the electrochemical tests were carried out by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.6 M NaCl electrolyte. The PTA coatings, with thicknesses ranging from 2 to 3 mm, with low porosity (0.9 % +/- 0.4 % vol. to 3.3 % +/- 0.7 % vol.) exhibited a dilution ranging from 18 % to 75 %. Coatings offered good wear resistance similar to 3.5 x 10(-4) mm(3)center dot N-1 center dot m(-1) and high resistance to corrosion, with corrosion current density as low as 0.04 mu A center dot cm(-2) with enlarged passivation plateau of similar to 1000 mV. These results demonstrate the application appeal of MPEAs as protective coatings produced on carbon steel structures to endure corrosive threats by using industrial coating processes. (AU)

• FAPESP's process: 22/02770-7 - Integrated Computational Materials Engineering ICME: applied to modeling, production, characterization and testing high entropy alloys
• Grantee: Francisco Gil Coury
• Support Opportunities: Research Grants - Initial Project