Tribological Properties of Solid Solution Strengthened Laser Cladded NiCrBSi/WC-12Co Metal Matrix Composite Coatings

Abstract

NiCrBSi, WC-12Co and NiCrBSi with 30, 40 and 50 wt.% WC-12Co coatings were produced on low carbon steel by laser cladding with an Nd:YAG laser with a multi-jet coaxial cladding-nozzle. The microstructure properties after WC-12Co alloying were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and Vickers hardness tests. The resulting microstructures consisted of a γ-Ni and Ni3B matrix, strengthened with Co and W, Ni3Si, CrB, Cr7C3, Cr23C6, WC/W2C phases. In coatings with 30, 40 and 50 wt.% WC-12Co, a solid solution, strengthened multi-matrix NiCrWCo phase formed, which yielded a higher matrix hardness. Wear tests that monitored the friction coefficients were performed with a tribometer that contained a ball-on-disc configuration, Al2O3 counter-body and reciprocal sliding mode at room temperature. The major wear mode on the NiCrBSi coatings without the WC-12Co was adhesive with a high wear rate and visible material loss by flaking, delamination and micro-ploughing. The addition of WC-12Co to the NiCrBSi coating significantly increased the wear resistance and changed the major wear mechanism from adhesion to three-body abrasion and fatigue wear.

Tribological performance of Ni-Cr-B-Si coatings deposited via laser cladding process

“…The average microhardness of the coatings' surfaces showed only a small difference: C1 -580 HV 1 , C2 -550 HV 1, and C3 -530 HV 1 , despite the relatively disparate deposition parameters used. Nonetheless, a hypothesis test performed in the ®MS Excel software confirmed that they are indeed statistically different, which is in accordance with the literature [16] [25], where hardness reduces for coatings that were deposited faster and that presented higher dilution values. Figures 5(a) and (b) show a comparison between C1, C2, and C3 hardness, scanning speed, and overall dilution.…”

“…An increased irregularity in C2 and C3 worn tracks was another indication of their higher wear. Similar considerations are presented in the literature [15,25]. Figure 13(a) shows a worn track profile obtained via the interferometry of a sample tested from C1, while figure 13(b) shows the SEM image of the worn ball used as the counterbody.…”

“…Bergan et al investigated NiCrBSi coatings with and without WC/12Co addition. In the matrix, authors detected adhesion wear mode, given the removal and repeated deformation of the material, besides microploughings and microcuttings, resulting from the detachment of abrasive particles from the coating and counterbody (Al 2 O 3 ), establishing three-body interfaces [25].…”

“…-The resulting debris was not analyzed. [25] NiCrBSi+WC-12Co/Laser Cladding -The performance of NiCrBSi coatings without and with addition of 30%-50% WC-12Co deposited via laser cladding on carbon steel substrate was investigated.…”

Küresel Grafitli Dökme Demir Kalıp Malzemesi Üzerine Farklı Toz Malzemeleri Kullanılarak Lazer Dolgu Kaynağı Uygulaması

“…Yüksek performanslı lazer kaplama malzemeleri üzerine yapılan araştırmalar son yıllarda artmaktadır [5][6][7][8]. Wang ve ark.…”