Microstructure and Wear Resistance of a Ni–Fe–Co–P/CeO2 Composite Coating after Heat Treatment

To extend the service time of #45 steel, Ni–Fe–Co–P alloy coatings were prepared on workpieces. CeO2 nanoparticles were also added and a heat treatment was carried out. Both the addition of CeO2 nanoparticles and the heat treatment had a positive influence on the dispersion strengthening, the fine grain strengthening, and the pinning effect. The surface topography and the chemical composition of the coatings as well as the microstructure were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDS), and X-ray diffraction (XRD). The microhardness was tested with a Duramin-40 hardness tester. The wear resistance reflected by the wear mark was observed by a LEXT4100 laser confocal microscope The coating with the stable intermetallic compounds and the highest wear resistance were obtained for a CeO2 nanoparticles content of 1g/L and a heat treatment temperature of 400°C because the main phase is NiP3 and the wear mark is the smallest for these parameters.