Optimization of the Si₃N₄ coating formation through plasma spraying on Inconel 738

ABSTRACT

In the present study, the deposition of silicon nitride (Si₃N₄) coating on Inconel 738 through plasma spray has been investigated. For producing the Si₃N₄ coating, different times (6, 8 and 10 s), different distances of the plasma spray torch from the substrate (30, 35 and 40 mm) and different currents for plasma spraying (3000, 3250 and 3500 A) were employed. For the characterisation of the coatings, SEM (thickness), XRD, micro-hardness and adhesion of the samples were measured. The coatings’ surface morphology was investigated through SEM. Based on the experimental results, by using a spraying time of 10 s, a distance of the torch of 40 mm and a current of 3500 A, high microhardness and adhesion of the coatings are obtained. On the other hand, the thickness of the coating increased by reducing the distance and increasing spray time and current.

KEYWORDS:

• Plasma spray coating
• response surface methodology
• Si₃N₄ coating
• Inconel 738
• multi-objective optimisation
• coatings
• hardness
• superalloys

Acknowledgements

Pasquale Cavaliere: Methodology, Investigation, Writing – original draft, Visualization, Supervision. Mojtaba Najafizadeh: Conceptualization, Methodology. Mehran Ghasempour-Mouziraji: Methodology. Constantinos Goulas: Methodology. Morteza Hosseinzadeh: Methodology. Mansoor Bozorg: Methodology, Supervision. Angelo Perrone: Methodology. Serena Perrone: Methodology.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

Data will be made available on request.