Microstructure and Performance of Ni/TiN Coatings Deposited by Laser Melting Deposition on 40Cr Substrates

Abstract

The current study reports the successful preparation of Ni/TiN coatings via laser melting deposition (LMD) for repairing the shaft of an electric submersible pump (ESP). The surface morphology, microstructure, phase composition, microhardness, shear strength, and wear resistance were investigated using a scanning electron microscope (SEM), X-ray diffractometer (XRD), microhardness meter, shear strength test machine, and friction and wear tester. Among the three coatings, the Ni/TiN coating deposited at 1.5 kW processed fine grains with an evenly dispersed and compact structure. The Ni/TiN coating revealed a face-centered cubic (f c c) lattice that exhibited diverse orientations due to the laser powers. The Ni/TiN coating deposited at 1 kW had the lowest average microhardness of 768 HV, while the Ni/TiN coating deposited at 1.5 kW had the highest average hardness of 843 HV. The shear displacements of the Ni/TiN coatings obtained at 1, 1.5, and 2 kW were 0.68, 0.54, and 0.61 mm, respectively. The Ni/TiN coating deposited at 1.5 kW had the lowest friction coefficient among all coatings, with an average value of only 0.44. Additionally, the Ni/TiN coating deposited at 1.5 kW exhibited the highest wear resistance. The presence of Ni, Ti, N, Cr, and Fe elements on the surface of the shaft of the ESP, indicated that the LMD technology had successfully repaired the shaft.

Effect of substrate’s surface roughness on corrosion and wear rate of Ni-GO nanocomposite coating

“…Based on the experimentation conducted, it was observed that the microhardness values of Ni-GO nanocomposite coating varied depending on the roughness of the substrate surface. These findings suggest that the smooth substrate provides a higher microhardness value, indicating better mechanical properties and potentially improved performance of the coating [12]. This information is important as it suggests that optimizing the smoothness of the substrate surface can lead to improved mechanical properties and performance of the Ni-GO nanocomposite coating.…”

Effect of defocused electron beam surface Ni/VC alloying on microstructure and properties of 40Cr steel

“…However, the surface will fail and the service life will be seriously reduced in the working environment such as wear, tear and corrosion for a long time [3,4]. Therefore, it is necessary to modify the surface of 40Cr steel by adding alloy elements [5,6]. As a solid solution element, Ni is usually dissolved in ferrite or austenite and plays a role in solid solution strengthening [7].…”