The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.O...The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.Overall,the cemented carbides with WC_(UF)/(W+C)_(UF) additives are almost fully densification to be higher than 99%,and the average grain size is kept above 2.8μm.The WC_(UF) additive assists grains to(truncated)trigonal prism shape by two dimensional(2D) growth,whereas the(W+C)_(UF) additive assists grains to rounded shape by three dimensional(3D) growth,lowers WC contiguity and increases face-centered-cubic Co.The hardness and bending strength of(75WC_(C)-15WC_(UF))-10Co are 86.6 HRA and 2 272 MPa,respectively,both higher than those of(75WC_(C)-15(W+C)_(UF))-10Co,which could be ascribed to the enhanced densification and unblemished grains.However,the fracture toughness of the(75WC_(C)-15(W+C)_(UF))-10Co is 23.5 MPa·m^(1/2),higher than that of the(75WC_(C)-15WC_(UF))-10Co due to the uniform WC-Co structure and flexible binder phase.展开更多
Ni nanoparticles were coated uniformly on the surface of WC powder via a facile electroless plating method(abbreviated as WCN-EP),and then consolidated for mechanical and corrosion resistance performance characterizat...Ni nanoparticles were coated uniformly on the surface of WC powder via a facile electroless plating method(abbreviated as WCN-EP),and then consolidated for mechanical and corrosion resistance performance characterization,in comparison with hand mixed WC-Ni(WCN-H).Under the optimized electroless plating parameters,Ni particles,less than 1μm in average diameter,were found to be uniformly and densely wrapped on the surface of the tungsten carbide matrix of WCN-EP.In comparison,in WCN-H,the Ni particles about 1.8μm in average diameter,were randomly distributed together with irregular WC particles.The uniform coating of Ni was found to assist the densification process of WCN-EP effectively,with higher densities and less pores than those of WCN-H at the Ni content of 10.6wt%,25.5wt%,and 30.3 wt%.However,at the Ni content of 18.8wt%,the relative densities of WCN-EP and WCN-H both increased to the maximum value of 98%.The maximum hardness of the consolidated WCN-EP was 82.6 HRA,about 1.2 HRA higher than that of WCN-H.In addition,the consolidated WCN-EP also exhibits a superior corrosion resistance by the polarization curve analysis at an electrochemical workstation.展开更多
基金Funded by the Technology Innovation Leading Program of Shaanxi(No.2022QFY08-02)。
文摘The effects of ultrafine WC(WC_(UF),0.5μm) or W(1μm) and C(0.3μm)(W+C)_(UF) additives on the densification,microstructure and mechanical properties of coarse-grained cemented carbides were compared systematically.Overall,the cemented carbides with WC_(UF)/(W+C)_(UF) additives are almost fully densification to be higher than 99%,and the average grain size is kept above 2.8μm.The WC_(UF) additive assists grains to(truncated)trigonal prism shape by two dimensional(2D) growth,whereas the(W+C)_(UF) additive assists grains to rounded shape by three dimensional(3D) growth,lowers WC contiguity and increases face-centered-cubic Co.The hardness and bending strength of(75WC_(C)-15WC_(UF))-10Co are 86.6 HRA and 2 272 MPa,respectively,both higher than those of(75WC_(C)-15(W+C)_(UF))-10Co,which could be ascribed to the enhanced densification and unblemished grains.However,the fracture toughness of the(75WC_(C)-15(W+C)_(UF))-10Co is 23.5 MPa·m^(1/2),higher than that of the(75WC_(C)-15WC_(UF))-10Co due to the uniform WC-Co structure and flexible binder phase.
基金Funded by the National Natural Science Foundation of China(Nos.51778213 and 52078189)the Fundamental Research Funds for the Central Universities of China(No.B200202073)。
文摘Ni nanoparticles were coated uniformly on the surface of WC powder via a facile electroless plating method(abbreviated as WCN-EP),and then consolidated for mechanical and corrosion resistance performance characterization,in comparison with hand mixed WC-Ni(WCN-H).Under the optimized electroless plating parameters,Ni particles,less than 1μm in average diameter,were found to be uniformly and densely wrapped on the surface of the tungsten carbide matrix of WCN-EP.In comparison,in WCN-H,the Ni particles about 1.8μm in average diameter,were randomly distributed together with irregular WC particles.The uniform coating of Ni was found to assist the densification process of WCN-EP effectively,with higher densities and less pores than those of WCN-H at the Ni content of 10.6wt%,25.5wt%,and 30.3 wt%.However,at the Ni content of 18.8wt%,the relative densities of WCN-EP and WCN-H both increased to the maximum value of 98%.The maximum hardness of the consolidated WCN-EP was 82.6 HRA,about 1.2 HRA higher than that of WCN-H.In addition,the consolidated WCN-EP also exhibits a superior corrosion resistance by the polarization curve analysis at an electrochemical workstation.
