Impact of CeO2 modification on the quality and wear performance of Al2O3/SiC reinforced metal-based coatings

In the pursuit of enhancing the quality and performance of metal-based composite coatings, we utilized Al2O3 and SiC as reinforcement particles to create Ni62 composite coatings on 65Mn surfaces through laser cladding. This study systematically delves into the influence of various mass fractions of CeO2 on the coating's forming quality and wear resistance. An in-depth analysis of the friction and wear mechanisms of these composite coatings is presented, with particular emphasis on CeO2's inhibitory effect on coating cracks. Our research findings reveal that the addition of an appropriate quantity of CeO2 can notably enhance the surface quality of the coating. However, an excessive amount of CeO2 can introduce defects on the coating surface. Within the central part of the cladding layer, longitudinal cracks propagate horizontally, forming what we term "r-type" cracks. Simultaneously, cracks extend both horizontally and vertically at the bonding interface, creating "T-type" cracks. CeO2 enhances the melt pool's fluidity, reducing the occurrence of pores and inclusions within the cladding layer. It also improves the dispersion of hard ceramic particles within the cladding layer, leading to a more uniform distribution of Cr and Ni elements within the coating. This refinement of grain structure in the coating reduces stress concentration and sensitivity to crack formation. Furthermore, the addition of CeO2 results in the accumulation of Ce elements on the coating surface. This accumulation promotes the movement of ceramic particles within the cladding layer towards the coating surface, ultimately forming a dense protective film on the surface. This protective film includes a new phase known as AlNi3. The primary wear mode observed in the composite coating is abrasive wear, with a minor presence of adhesive wear. Importantly, the incorporation of CeO2 significantly enhances the wear resistance of the composite coating.