This article explored the influence of molding density of TiO<sub>2</sub> varistor-ceramic on densification of ceramic body and grain growth. By the main phase and second phase analysis of TiO<sub>2&...This article explored the influence of molding density of TiO<sub>2</sub> varistor-ceramic on densification of ceramic body and grain growth. By the main phase and second phase analysis of TiO<sub>2</sub> varistor-ceramic through XRD and EDAX, the effects of the second phrase on TiO<sub>2</sub> varistor-ceramic were studied. Grain size and its distribution were observed through scanning electron microscope and the density of porcelain body was measured. The effects of grain size, distribution and density of ceramic body on electrical property of TiO<sub>2</sub> varistor-ceramic were the focus issue for analysis. The increased molding density would improve the densifying of magnetic body to some extent and promote grain growth.展开更多
In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discusse...In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discussed. The microstructure evolution and surface morphologies of the samples were characterized by using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM). The experimental results show that sample by high current pulsed electron beam treatment surface melting, martensitic phase transformation occurred, and volcanic crater morphology and fine microstructure in the remelted layer surface;with the increase of number of pulses, after processing the microhardness of the samples also with the increase, 15-pulsed sample microhardness than the original sample increased by 30.9%. Corrosion resistance of samples was studied with the impedance diagram and polarization curve. The electrochemical results show that corrosion resistance of samples by high current pulsed electron beam treatment presents different degrees of change, the 5-pulsed sample in 1 mol HNO<sub>3</sub> solution corrosion of the best, and 15-pulsed sample corrosion resistance is even lower than the original sample. Grain refinement, martensite transformation, dislocation and deformation twins are the main reasons for improving the micro hardness and corrosion resistance of the samples.展开更多
In this paper, Al/Ni/TiC powders were mixed on the surface of A380 aluminum alloy, by selecting appropriate laser parameters;the cladding layer with good adhesion to the substrate was obtained. The microstructure and ...In this paper, Al/Ni/TiC powders were mixed on the surface of A380 aluminum alloy, by selecting appropriate laser parameters;the cladding layer with good adhesion to the substrate was obtained. The microstructure and properties of the cladding layer under different laser parameters were analyzed. The results show that: the phase composition of the cladding layer is mainly composed of TiC, Al, Ni, C and Ti phases. The hardness of the cladding region is up to 173.3 HV, which is about 2.9 times the matrix (–59.1 HV). The corrosion voltage (–1.8 V) of the cladding layer shifted significantly from the corrosion potential (–1.18 V), the corrosion current density increased, the resistance value decreased and the diameter of the capacitor arc decreased;all these phenomena indicate that the corrosion resistance of the cladding layer is decreased.展开更多
文摘This article explored the influence of molding density of TiO<sub>2</sub> varistor-ceramic on densification of ceramic body and grain growth. By the main phase and second phase analysis of TiO<sub>2</sub> varistor-ceramic through XRD and EDAX, the effects of the second phrase on TiO<sub>2</sub> varistor-ceramic were studied. Grain size and its distribution were observed through scanning electron microscope and the density of porcelain body was measured. The effects of grain size, distribution and density of ceramic body on electrical property of TiO<sub>2</sub> varistor-ceramic were the focus issue for analysis. The increased molding density would improve the densifying of magnetic body to some extent and promote grain growth.
文摘In this paper, the changes of surface morphology, microstructure, hardness and corrosion resistance of industrial pure zirconium before and after surface modification by high current pulsed electron beam were discussed. The microstructure evolution and surface morphologies of the samples were characterized by using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM). The experimental results show that sample by high current pulsed electron beam treatment surface melting, martensitic phase transformation occurred, and volcanic crater morphology and fine microstructure in the remelted layer surface;with the increase of number of pulses, after processing the microhardness of the samples also with the increase, 15-pulsed sample microhardness than the original sample increased by 30.9%. Corrosion resistance of samples was studied with the impedance diagram and polarization curve. The electrochemical results show that corrosion resistance of samples by high current pulsed electron beam treatment presents different degrees of change, the 5-pulsed sample in 1 mol HNO<sub>3</sub> solution corrosion of the best, and 15-pulsed sample corrosion resistance is even lower than the original sample. Grain refinement, martensite transformation, dislocation and deformation twins are the main reasons for improving the micro hardness and corrosion resistance of the samples.
文摘In this paper, Al/Ni/TiC powders were mixed on the surface of A380 aluminum alloy, by selecting appropriate laser parameters;the cladding layer with good adhesion to the substrate was obtained. The microstructure and properties of the cladding layer under different laser parameters were analyzed. The results show that: the phase composition of the cladding layer is mainly composed of TiC, Al, Ni, C and Ti phases. The hardness of the cladding region is up to 173.3 HV, which is about 2.9 times the matrix (–59.1 HV). The corrosion voltage (–1.8 V) of the cladding layer shifted significantly from the corrosion potential (–1.18 V), the corrosion current density increased, the resistance value decreased and the diameter of the capacitor arc decreased;all these phenomena indicate that the corrosion resistance of the cladding layer is decreased.
