Characterization of electrodeposited Ni–Cr/hBN composite coatings

• Published in: Journal of alloys and compounds Vol. 844; p. 155511
• Main Authors: Demir, Mehmet, Kanca, Erdoğan, Karahan, İsmail Hakki
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 05-12-2020; Elsevier BV
• Subjects: Abrasion resistant alloys; Abrasion resistant coatings; Abrasion resistant steels; Coated electrodes; Coating; Coefficient of friction; Corrosion; Corrosion resistance; Corrosion tests; Corrosive wear; Cracks; Electrodeposition; Free surfaces; Low carbon steels; Mechanical properties; Microhardness; Nanohardness; Nanoindentation; Nickel chromium alloys; Ni–Cr/hBN nanocomposites; Protective coatings; Solid lubricants; Substrates; Wear; Wear resistance; Wear tests; X-ray diffraction; Electrodeposition; Coating; Ni–Cr/hBN nanocomposites; Corrosion; Wear; Nanoindentation
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.155511

In this study, Ni–Cr/hBN composite coatings with different hBN content were deposited on AISI 1040 mild carbon steel using electrodeposition. The coatings were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), cyclic voltammetry (CV), 2D surface profilometery, nano-indentation, corrosion and wear tests. While some cracks were observed in the Ni–Cr alloy coatings, more compact and crack-free surfaces were obtained in the Ni–Cr/hBN composite coatings under all deposition conditions. XRD analysis of the Ni–Cr/hBN layer revealed the presence of a predominant Ni phase with Cr, Cr2Ni3B6, (Ni2Cr23)0.16, and hBN phases in the structure. Depending on deposition parameters, the microhardness and nanohardness of the Ni–Cr and Ni–Cr/hBN coatings were found to range between 308 and 538 HV and 1,86–7,69 GPa respectively. hBN acted as a solid lubricant in the wear tests; the friction coefficient decreased and wear resistance was improved. Among the composite coatings, the corrosion resistance of the coating with 20 g/l hBN was found to be 12 and 3.3 times higher than the steel substrate and Ni–Cr alloy, respectively. The hBN additive provided better mechanical properties and corrosion resistance in the range of 5–20 g/l hBN, but after 20 g/l hBN agglomeration became a problem and impaired the mechanical properties. The highest corrosion and abrasion resistance was obtained with 20 g/l hBN.
•Ni–Cr/hBN composite coatings were fabricated by pulse current electrodeposition.•Effect of hBN addition on the mechanical properties and corrosion resistance of Ni–Cr coatings were investigated.•The cracks in Ni–Cr coatings were prevented by hBN addition.•hBN addition improved the hardness, wear resistance and corrosion resistance.•20 g/l hBN provided the best corrosion and wear resistance.