Growth Characteristics and Reinforcing Behavior of In-situ NbCp in Laser Cladded Fe-based Composite Coating

Over the past decade, researchers demonstrated much interest in laser cladded metal matrix composite coatings for its good wear resistance. In this paper, in-situ NbCp reinforced Fe-based wear-resistance coatings with different designed NbC contents were produced by laser cladding. The formation mechanism of NbC particle was analyzed. The effects of NbC content on the microstructure and mechanical properties of coatings were investigated. It was revealed that α-(Fe, Cr), (Fe, Cr)7C3, NbC existed in all coatings. NbC particles formed by the chemical reaction of Nb and C dissolved in the molten pool. The increase of designed NbC content led to the growth of the porosity amount, and the increase of the size and the area ratio of the particle, as well as the transformation of the NbCp morphology from quadrangle to petaloid shape. Moreover, the micro-hardness and the wear resistance of the coating were improved with the increase of NbC. When NbCp content was 30 wt%, the mechanical properties decreased slightly.