Synthesis and characterization of Ni-based infiltration brazed coating reinforced with Co-P shell-coated WC

In this work the interface and wear resistance of Ni/WC infiltration-brazed cladding was increased by incorporating WC@Co-P reinforcements. This was achieved by depositing a Co-P nano-shell on the WC particles using the electroless plating technique. The morphology of the powders and the thickness of the Co-P shell were examined using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The phase compositions were analyzed through energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results revealed that by optimizing the parameters of the electroless plating bath, a uniform Co-P shell with an average thickness of 80 nm was successfully deposited onto the WC particles. Through FESEM and EDS analyses, it was observed that the WC@Co-P/NiCrBSi coating exhibited higher compactness compared to conventional Ni/WC coating, along with a more homogeneous distribution of reinforcements. Additionally, unlike WC/NiCrBSi coating, no abnormal growth of particles occurred during molten phase sintering. Underpinning these findings are results from Pin-On-Disk tests which demonstrated notable improvements in various wear properties for the Co-P modified coating compared to conventional Ni/WC coating. Specifically, there was a 33 % increase in the coefficient of friction (0.3), a 40 % reduction in wear rate (0.006 g/Km), and a 26 % increase in hardness (1500 Vickers). These enhancements highlight the potential benefits offered by incorporating WC@Co-P reinforcements in improving interface quality and wear behavior for Ni/WC infiltration-brazed coating materials .