WC?10Co?4Cr and Cr3C2?25NiCr coatings were deposited on H13 steel by high velocity oxy fuel (HVOF) spraying. To enhance the thermal stability of the WC?10Co?4Cr coating, NiCr powders were sprayed between the surface c...WC?10Co?4Cr and Cr3C2?25NiCr coatings were deposited on H13 steel by high velocity oxy fuel (HVOF) spraying. To enhance the thermal stability of the WC?10Co?4Cr coating, NiCr powders were sprayed between the surface coating and substrate. The microstructures of the surface and cross section, thermal shock and wear resistance of these two coatings were investigated in detail. The carbon diffusion in the two coatings was explained from the view of the thermodynamic. And the adhesive strength of Cr3C2?25NiCr coating (64.40 MPa) is almost the same as that of WC?10Co?4Cr coating (61.69 MPa). The friction tests show that the Cr3C2?25NiCr coating has higher friction coefficient than the WC?10Co?4Cr coating at both 500 and 600 °C. The wear resistance of the Cr3C2?25NiCr coating is better than that of the WC?10Co?4Cr coating.展开更多
Using plasma build-up welding technology, Ni60, WC, Cr3C2, and TiC composite powders were clad on the surface of the substrate in a certain proportion according to the metallurgical bonding method to increase the bond...Using plasma build-up welding technology, Ni60, WC, Cr3C2, and TiC composite powders were clad on the surface of the substrate in a certain proportion according to the metallurgical bonding method to increase the bond strength between the coating and the substrate. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microstructure of the surfacing layer and the chemical composition of the sample. The hardness and wear resistance of the surfacing layer were tested and analyzed by the HV-1000 hardness tester and the impact wear device. The results showed that in the microstructure, fishbone, spider-web, and floral-like structures appeared in the surfacing layer. When the micro-hardness was tested, the depth of the indentation reflected the hardness of the surfacing layer. When analyzing wear resistance, the amount of wear increases with time.展开更多
The effect of addition of metallic carbides Cr3C2 and Cr3C2 + VC on structure and mechanical properties of WC-10 wt% Co nanocomposites have been studied. After preparing and compacting of the powders under pressure of...The effect of addition of metallic carbides Cr3C2 and Cr3C2 + VC on structure and mechanical properties of WC-10 wt% Co nanocomposites have been studied. After preparing and compacting of the powders under pressure of 200 MPa, the samples were sintered at temperatures of 1370°C, 1410°C and 1450°C for 1 hour. Microstructural examinations by SEM show that the average grain size obtained for Cr3C2 + VC added alloys reduced 50 percent and also grain size distribution was narrower compared to those samples without grain growth inhibitors. Furthermore, co-addition of Cr3C2 and VC rise to a higher Vickers hardness and fracture toughness of the sintered alloys at 1410°C.展开更多
基金Project(51371200)supported by the National Natural Science Foundation of ChinaProject(2014CB644000)supported by the National Basic Research Program of ChinaProject(502044009)supported by the Fundamental Research Funds for the Central Universities,China
文摘WC?10Co?4Cr and Cr3C2?25NiCr coatings were deposited on H13 steel by high velocity oxy fuel (HVOF) spraying. To enhance the thermal stability of the WC?10Co?4Cr coating, NiCr powders were sprayed between the surface coating and substrate. The microstructures of the surface and cross section, thermal shock and wear resistance of these two coatings were investigated in detail. The carbon diffusion in the two coatings was explained from the view of the thermodynamic. And the adhesive strength of Cr3C2?25NiCr coating (64.40 MPa) is almost the same as that of WC?10Co?4Cr coating (61.69 MPa). The friction tests show that the Cr3C2?25NiCr coating has higher friction coefficient than the WC?10Co?4Cr coating at both 500 and 600 °C. The wear resistance of the Cr3C2?25NiCr coating is better than that of the WC?10Co?4Cr coating.
基金Funded by the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2014RCJJ041)the National Natural Science Foundation of China(51774199)
文摘Using plasma build-up welding technology, Ni60, WC, Cr3C2, and TiC composite powders were clad on the surface of the substrate in a certain proportion according to the metallurgical bonding method to increase the bond strength between the coating and the substrate. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microstructure of the surfacing layer and the chemical composition of the sample. The hardness and wear resistance of the surfacing layer were tested and analyzed by the HV-1000 hardness tester and the impact wear device. The results showed that in the microstructure, fishbone, spider-web, and floral-like structures appeared in the surfacing layer. When the micro-hardness was tested, the depth of the indentation reflected the hardness of the surfacing layer. When analyzing wear resistance, the amount of wear increases with time.
文摘The effect of addition of metallic carbides Cr3C2 and Cr3C2 + VC on structure and mechanical properties of WC-10 wt% Co nanocomposites have been studied. After preparing and compacting of the powders under pressure of 200 MPa, the samples were sintered at temperatures of 1370°C, 1410°C and 1450°C for 1 hour. Microstructural examinations by SEM show that the average grain size obtained for Cr3C2 + VC added alloys reduced 50 percent and also grain size distribution was narrower compared to those samples without grain growth inhibitors. Furthermore, co-addition of Cr3C2 and VC rise to a higher Vickers hardness and fracture toughness of the sintered alloys at 1410°C.
