Effect of post-coating technique on microstructure, microhardness and the mixed lubrication regime parameters of thermally-sprayed NiCrBSi coatings

Effect of post-coating technique on microstructure, microhardness and the mixed lubrication regime parameters of thermally-sprayed NiCrBSi coatings

The purpose of this paper is to understand and to quantify the effect of the re-melting technique on the microstructure and tribological behaviour of oxy-fuel (OF) thermally sprayed NiCrBSi coatings in the mixed lubrication regime. Two different re-melting techniques have been used: Surface Flame Me...

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Bibliographic Details
Published in:Surface & coatings technology Vol. 358; pp. 824 - 832
Main Authors: Habib, K.A., Cano, D.L., Heredia, José Antonio, Mira, J.S.
Format: Journal Article
Language:English
Published: Lausanne Elsevier B.V 25-01-2019
Elsevier BV
Subjects:
Coating effects
Coefficient of friction
Contact pressure
Energy dispersive X ray spectroscopy
Hardness tests
Indentation
Laser re-melting
Lubrication
Melting
Microhardness
Microstructure
Mixed lubrication regime parameters
Morphology
NiCrBSi
Oxy-fuel
Parameters
Regression models
Robustness (mathematics)
Scanning electron microscopy
Tribology
Ultrasonic testing
Wear
X-ray diffraction
NiCrBSi
Mixed lubrication regime parameters
Laser re-melting
Wear
Oxy-fuel
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Summary:The purpose of this paper is to understand and to quantify the effect of the re-melting technique on the microstructure and tribological behaviour of oxy-fuel (OF) thermally sprayed NiCrBSi coatings in the mixed lubrication regime. Two different re-melting techniques have been used: Surface Flame Melting (SFM) and laser re-melting processes. The microstructure of the obtained coatings was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Deposited coatings demonstrated similar phases but manifested notable differences in their morphology, size, distribution and relative proportions of the observable phases. These differences in microstructure may explain the differences in coating properties. Tribological experiments were carried out using a pin-on-disc approach at different sliding speeds and contact pressures. Wear and indentation tests have also been conducted. Laser re-melted coatings achieve higher hardness, less friction and lower accumulated wear volume in lubricated conditions. Test data were fitted with regression models. The fitted equations allow a robust assessment of the effect of the re-melting technique and working conditions on the friction coefficient in components that operate in the mixed lubrication regime. Therefore, these equations may help to select the adequate coating and tribological parameters for specific applications. [Display omitted] •Laser and flame re-melting processes result in different coating microstructure.•Laser re-melting coatings show better tribological properties than flame re-melting.•Re-melting affects the stability of the lubricant layer and its interaction with the surface coating.•A fitted model allows to select the lubricated working conditions to control friction and wear
ISSN:0257-8972
1879-3347
DOI:10.1016/j.surfcoat.2018.12.004