Effect of Ultra-fine WC Particles on Microstructural Evolution and Wear Behavior of Ni-Based Nano-CeO2 Coatings Produced by Laser

The wear behavior and microstructure of CO2 laser cladded Ni-based alloy coatings with 1 wt% nano-CeO2 and 20 wt% WC addition (CeO2/Ni) was compared with Ni-based coatings with 1 wt% nano-CeO2 addition (WC-CeO2/Ni). Both coatings were cladded on 30CrMnSiNi2A steel with good metallurgical bounding to substrate. The influence of ultra-fine carbide WC on the microstructure of WC-CeO2/Ni alloy composite coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and electron probe micro analysis (EPMA). WC addition increased M23C6 content, but decreased the M7C3. The comparison of comprehensive mechanical properties between coatings with and without fine WC particles was conducted on Vickers hardness and wear-resistance test system. Results indicate that the performance of WC-CeO2/Ni is better than that of CeO2/Ni metal matrix composition (MMC). Few hot cracks appeared in Ni-based WC-CeO2 MMC production, which were investigated by SEM and EDS. The crack mechanism can be claimed as Fe dilution and coefficient of thermal expansion for WC-CeO2/Ni MMC differed from that of base material 30CrMnSiNi2A steel.