Microstructure and Wear Behaviors of WC/Ni60 Particle reinforced Composite Coatings by Laser Micro-cladding

摘要

In order to improve service life, WC particles reinforced Ni60-base composite coatings were fabricated by laser micro-cladding technology on Q235 Inner cylinder surface. The microstructures and phases of the coating were observed and analyzed by scanning electron microscopy(SEM), X-Ray diffraction (XRD)and energy dispersive spectrometer(EDS). The cross-section micro-hardness of the cladding layer measured by Vickers hardness tester, and the abrasion performance of the coatings characterized through the friction and wear experiments. The results show that the phase of the laser cladding coatings is mainly composed of carbides and y-(Ni, Cr, Fe) solid solution. The WC particles melted partially and precipitated in the middle-upper of the coatings and precipitated fine dendrites; some WC particles were cracked or broken in the bottom of the coatings. The average micro-hardness value of the coating is 896HV0.2, which is 5. 74 times higher than that of the substrate. Under the effect of solution strengthening, diffusion eutectic aggrandizement, hard phase strengthening and fine-crystal strengthening,the weight loss of the coatings decreased obviously. Compared with the substrate, the weight loss of modified layer is only about 0. 2 times under the same condition. The wear behaviors of the laser clad composite coatings are improved significantly.