Surface modification of (DS) coatings based on Ni-Cr-Al by pulsed plasma treatment (PPT) method

Abstract

To safeguard materials against abrasive corrosion, various thermal spraying techniques can be employed, including powder spraying with a gas flame, plasma spraying, deposition and melting, high-speed oxygen-gas spraying, and detonation spraying. Thermal spraying is highly effective for protecting materials from wear and corrosion, thus extending their service life. This article discusses the changes in the surface of Ni-Cr-Al coatings subjected to pulsed plasma treatment using a plasma generator. The coatings were initially applied via detonation spraying (DS) and then underwent pulsed plasma treatment (PPT). The study investigates alterations in the structural and phase states of the coatings under plasma exposure. A comprehensive analysis of the detonation Ni-Cr-Al coatings' characteristics was conducted using scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), surface roughness measurements, hardness tests, and tribological assessments. The findings indicate that pulsed plasma treatment enhances the wear resistance of the coatings' surface layer by reducing the coefficient of friction and increasing microhardness. X-ray phase analysis reveals that the improved tribomechanical properties of the treated surfaces are linked to an increased presence of CrNi₃, NiAl, and NiCr phases in the coatings.