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

Abstract

The wear behavior and microstructure of CO 2 laser cladded Ni-based alloy coatings with 1 wt% nano-CeO 2 and 20 wt% WC addition (CeO 2 /Ni) was compared with Ni-based coatings with 1 wt% nano-CeO 2 addition (WC-CeO 2 /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-CeO 2 /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 M 23 C 6 content, but decreased the M 7 C 3 . 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-CeO 2 /Ni is better than that of CeO 2 /Ni metal matrix composition (MMC). Few hot cracks appeared in Ni-based WC-CeO 2 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-CeO 2 /Ni MMC differed from that of base material 30CrMnSiNi2A steel.