Preparing And Properties Research Of Wear-Resisting Ceramic-Metal Composite Cladding Layers

Ceramic-metal composites have both metal plastic and ceramic high hardness properties and become a major topic in industrial and defense for its projecting performance. Based on the characteristics of laser cladding, WC and NbC reinforced Ni-based cladding layer were prepared on45steel by laser cladding. Microstructure and phase composition were tested by XRD and SEM and the hardness of the coatings were tested by hardness tester. Wear resistance of the coating were compared by high temperature erosion test and the coating’s surface morphology were observed by SEM.The results showed that the coating prepared by laser cladding were dense under reasonable parameters. The hardness test showed that the proportion of reinforced phase increased may lead to a higher hardness for the same material, while WC/Ni based coating were higher than NbC/Ni based for the same proportion of the reinforced phase,40%WC/Ni based coating’s hardness peak reached884.37HV. XRDresults showed that γ-Ni、W2C and Cr7C3were found in WC/Ni based coating and γ-Ni、 NbC and FeNbO4were found in NbC/Ni based coating. SEM and EDS results showed that all the coatings had a good metallurgical bond with the substrate, and the coatings are thinning with increasing of refinement phase. The eutectic structure of WC/Ni coating was formed by γ-Ni, the boundary of solid solution was filled by several elements, and the light gray strip organization and white particles were found in the middle and lower of the coating. NbC/Ni coating had the same organization as WC/Ni coating partly, while the white particles were changed to a petal-like tissue, which was determined by the crystal structure of NbC. The high temperature erosion results showed that the coatings had a light wear level under400℃while a severe level under800℃, which were caused by material shaping property and oxidation phenomena. Research between the angle and erosion results showed that all the coatings had a maximum erosion rate at40°while a minimum at90°, and40%WC had similar erosion rate at40°and60°. Besides, the weightlessness of the coatings was not obviously at the incubation period and tended to be stable with the time passing. Compared to45steel, the coating’s wear resistance were improved different level after cladding. In the low reinforced phase the erosion topography were filled by trench caused by cutting and in the high reinforced phase were mainly filled by embrittlement generated by extrusion.