MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, an...MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffraction and transmission electron microscopy. The magnetic properties of the samples were studied using a vibrating sample magnetometer. nanorods with a diameter of 35 nm and an The results indicated that pure Ni0.5-xZn0.5Fe2O4 aspect ratio of 15 were prepared. It was found that the diametei of the MnxNi0.5-xZn0.5Fe2O4（0≤x≤0.5） samples increased, the length and the aspect .ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7-8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coercivity of the samples again increased when the x value was higher than 0.4. When x=0.5, the coercivity of the MnxNi0.5-xZn0.5Fe2O4 sample reached the maximal value （134.3 Oe） at the calcination temperature of 600 ℃. The saturation magnetization of the samples first increased and then. decreased with the increase in the x value. When x=0.2, the saturation magnetizat：ion of the sample reached the maximal value （68.5 emu/g） at the calcination temperature of 800 ℃.展开更多
Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub&...Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.展开更多
This paper reports that <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers can be synthesized by an extremely simple and easy approach of inducing a reaction through the addition ...This paper reports that <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers can be synthesized by an extremely simple and easy approach of inducing a reaction through the addition of NaOH aqueous solution to a mixed aqueous solution of Bi(NO<sub>3</sub>)<sub>3</sub>·5H<sub>2</sub>O and HNO<sub>3</sub> scanning electron microscopy images of the Bi<sub>2</sub>O<sub>3</sub> microflowers indicate that the Bi<sub>2</sub>O<sub>3</sub> nanorods grew radially from the centre of the microflower to form the microflower shape. The findings of this study show that control of the reaction temperature, reaction time, and raw material mixture ratio plays an important role in the formation of <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers. It is especially revealed that <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers can be formed at low temperatures with short reaction times. It has thus far been reported that flower-shaped Bi<sub>2</sub>O<sub>3</sub> particles or their precursors can be synthesized by the addition of additives such as organic molecules or certain inorganic ions. The present work reports on the discovery of ways to synthesize flower-shaped Bi<sub>2</sub>O<sub>3</sub> particles without the use of special additives.展开更多
This paper reports that/3-Ga2O3 nanorods have been synthesized by ammoniating Ga2O3 films on a V middle layer deposited on Si（111） substrates. The synthesized nanorods were confirmed as monoclinic Ga2O3 by x-ray dif...This paper reports that/3-Ga2O3 nanorods have been synthesized by ammoniating Ga2O3 films on a V middle layer deposited on Si（111） substrates. The synthesized nanorods were confirmed as monoclinic Ga2O3 by x-ray diffraction,Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy reveal that the grown β-Ga2O3 nanorods have a smooth and clean surface with diameters ranging from 100 nm to 200 nm and lengths typically up to 2μm. High resolution TEM and selected-area electron diffraction shows that the nanorods are pure monoclinic Ga2O3 single crystal. The photoluminescence spectrum indicates that the Ga2O3 nanorods have a good emission property. The growth mechanism is discussed briefly.展开更多
Al2O3 matrix composites reinforced with Fe3Al nano-particles were fabricated by hot processing at 1 4501 600 ℃. The effect of Fe3Al content on the densification, mechanical properties and microstructure of the compos...Al2O3 matrix composites reinforced with Fe3Al nano-particles were fabricated by hot processing at 1 4501 600 ℃. The effect of Fe3Al content on the densification, mechanical properties and microstructure of the composites was investigated. The results show that some elongated Al2O3 grains are observed. Fe3Al particles are mainly situated at grain boundaries of the matrix while smaller particles are trapped within the alumina grains. The addition of Fe3Al nanoparticles improves the mechanical properties of alumina. The maximum strength and toughness of the Fe3Al/Al2O3 nanocomposites are 832 MPa and 7.96 MPa·m1/2, respectively.展开更多
文摘MnxNi0.5-xZn0.5Fe2O4 nanorods were successfully synthesized by the thermal treatment of rod-like precursors that were fabricated by the co-precipitation of Mn2＋, Ni2＋, and Fe2＋ in the lye. The phase, morphology, and particle diameter were examined by the X-ray diffraction and transmission electron microscopy. The magnetic properties of the samples were studied using a vibrating sample magnetometer. nanorods with a diameter of 35 nm and an The results indicated that pure Ni0.5-xZn0.5Fe2O4 aspect ratio of 15 were prepared. It was found that the diametei of the MnxNi0.5-xZn0.5Fe2O4（0≤x≤0.5） samples increased, the length and the aspect .ratio decreased, with an increase in x value. When x=0.5, the diameter and the aspect ratio of the sample reached up to 50 nm and 7-8, respectively. The coercivity of the samples first increased and then decreased with the increase in the x value. The coercivity of the samples again increased when the x value was higher than 0.4. When x=0.5, the coercivity of the MnxNi0.5-xZn0.5Fe2O4 sample reached the maximal value （134.3 Oe） at the calcination temperature of 600 ℃. The saturation magnetization of the samples first increased and then. decreased with the increase in the x value. When x=0.2, the saturation magnetizat：ion of the sample reached the maximal value （68.5 emu/g） at the calcination temperature of 800 ℃.
文摘Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.
文摘This paper reports that <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers can be synthesized by an extremely simple and easy approach of inducing a reaction through the addition of NaOH aqueous solution to a mixed aqueous solution of Bi(NO<sub>3</sub>)<sub>3</sub>·5H<sub>2</sub>O and HNO<sub>3</sub> scanning electron microscopy images of the Bi<sub>2</sub>O<sub>3</sub> microflowers indicate that the Bi<sub>2</sub>O<sub>3</sub> nanorods grew radially from the centre of the microflower to form the microflower shape. The findings of this study show that control of the reaction temperature, reaction time, and raw material mixture ratio plays an important role in the formation of <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers. It is especially revealed that <em>α</em>-Bi<sub>2</sub>O<sub>3</sub> microflowers can be formed at low temperatures with short reaction times. It has thus far been reported that flower-shaped Bi<sub>2</sub>O<sub>3</sub> particles or their precursors can be synthesized by the addition of additives such as organic molecules or certain inorganic ions. The present work reports on the discovery of ways to synthesize flower-shaped Bi<sub>2</sub>O<sub>3</sub> particles without the use of special additives.
基金Project supported by the State Key Program of the National Natural Science Foundation of China (Grant No 90201025)
文摘This paper reports that/3-Ga2O3 nanorods have been synthesized by ammoniating Ga2O3 films on a V middle layer deposited on Si（111） substrates. The synthesized nanorods were confirmed as monoclinic Ga2O3 by x-ray diffraction,Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy reveal that the grown β-Ga2O3 nanorods have a smooth and clean surface with diameters ranging from 100 nm to 200 nm and lengths typically up to 2μm. High resolution TEM and selected-area electron diffraction shows that the nanorods are pure monoclinic Ga2O3 single crystal. The photoluminescence spectrum indicates that the Ga2O3 nanorods have a good emission property. The growth mechanism is discussed briefly.
文摘Al2O3 matrix composites reinforced with Fe3Al nano-particles were fabricated by hot processing at 1 4501 600 ℃. The effect of Fe3Al content on the densification, mechanical properties and microstructure of the composites was investigated. The results show that some elongated Al2O3 grains are observed. Fe3Al particles are mainly situated at grain boundaries of the matrix while smaller particles are trapped within the alumina grains. The addition of Fe3Al nanoparticles improves the mechanical properties of alumina. The maximum strength and toughness of the Fe3Al/Al2O3 nanocomposites are 832 MPa and 7.96 MPa·m1/2, respectively.
