Agglomeration-free nanosized ZrO2-HfO2-Y2O3-Sc2O3 composite powders were successfully synthesized by Sol-Gel technique in heated aqueous solution of alcohol, using analytically pure ZrOCl2 · 8H2O, HfOCl2·8H2...Agglomeration-free nanosized ZrO2-HfO2-Y2O3-Sc2O3 composite powders were successfully synthesized by Sol-Gel technique in heated aqueous solution of alcohol, using analytically pure ZrOCl2 · 8H2O, HfOCl2·8H2O, Y（NO3）3·6H2O, and Sc2O3 as raw materials. The effect of synthesis condition on the size and dispersity of the composite powders was investigated by means of XRD, TEM, and TG-DSC techniques. The results showed that well-dispersed predecessor of ZrO2-HfO2-Y2O3-Sc2O3 composite nanopowders could be obtained. The optional condition ： PEG6000 as dispersant was 1%, alcohol/H2O ratio was 5/1, metallic ion concentration in whole solution was 0.5 mol·L^-1 and the pH value of the solution was 12. After calcined at 620 ℃, the powder obtained was in uniform cubic structure, and its average particle size was about 13 nm, which was good for producing nanocrystalline solid electrolyte.展开更多
Al2O3-ZrO2 with a high level of hardness and toughness is known as ceramic steel. Due to its unique properties it can be used as a reinforcement in fabrication of metal matrix composites. In this study, nanoparticles ...Al2O3-ZrO2 with a high level of hardness and toughness is known as ceramic steel. Due to its unique properties it can be used as a reinforcement in fabrication of metal matrix composites. In this study, nanoparticles of Al2O3-10% ZrO2 with an average size of 80 nm were used to fabricate Al matrix composites containing 0.5, 1, 1.5 and 2 wt.% of the reinforcement. The fabrication route was stir casting at 850?C. There is no report about usage of this reinforcement in fabrication of composites in the literature. The microstructures of the as-cast composites were studied by scanning electron microscope (SEM). Density measurement, hardness and tensile properties were carried out to identify the mechanical properties of the composites. The results revealed that with increasing the reinforcement content, density decreased while yield, ultimate tensile strength and compressive strength increased. Also, hardness increased by increasing the reinforcement content up to 1 wt.% Al2O3-10% ZrO2 but it decreased in the samples containing higher amounts of reinforcement.展开更多
γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents f...γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents from the γ-Fe transforming to α-Fe as rapidly cooling from high temperature to room temperature, The characteristics of the particles were examined at room temperature by TEM. electron diffraction and XRD. It was proved that about 70% of γ-Fe phase in the particles was present. In addition. the lattice constant of the γ-Fe was 0.364 nm in place of 0.360 nm展开更多
A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures an...A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.展开更多
以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO ...以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。展开更多
基金Project supported by the National Natural Science Foundation of China (20101006)Nano Technology Special Foundationof Shanghai Science and Technology Committee (0452nm073) and Shanghai Education Committee
文摘Agglomeration-free nanosized ZrO2-HfO2-Y2O3-Sc2O3 composite powders were successfully synthesized by Sol-Gel technique in heated aqueous solution of alcohol, using analytically pure ZrOCl2 · 8H2O, HfOCl2·8H2O, Y（NO3）3·6H2O, and Sc2O3 as raw materials. The effect of synthesis condition on the size and dispersity of the composite powders was investigated by means of XRD, TEM, and TG-DSC techniques. The results showed that well-dispersed predecessor of ZrO2-HfO2-Y2O3-Sc2O3 composite nanopowders could be obtained. The optional condition ： PEG6000 as dispersant was 1%, alcohol/H2O ratio was 5/1, metallic ion concentration in whole solution was 0.5 mol·L^-1 and the pH value of the solution was 12. After calcined at 620 ℃, the powder obtained was in uniform cubic structure, and its average particle size was about 13 nm, which was good for producing nanocrystalline solid electrolyte.
文摘Al2O3-ZrO2 with a high level of hardness and toughness is known as ceramic steel. Due to its unique properties it can be used as a reinforcement in fabrication of metal matrix composites. In this study, nanoparticles of Al2O3-10% ZrO2 with an average size of 80 nm were used to fabricate Al matrix composites containing 0.5, 1, 1.5 and 2 wt.% of the reinforcement. The fabrication route was stir casting at 850?C. There is no report about usage of this reinforcement in fabrication of composites in the literature. The microstructures of the as-cast composites were studied by scanning electron microscope (SEM). Density measurement, hardness and tensile properties were carried out to identify the mechanical properties of the composites. The results revealed that with increasing the reinforcement content, density decreased while yield, ultimate tensile strength and compressive strength increased. Also, hardness increased by increasing the reinforcement content up to 1 wt.% Al2O3-10% ZrO2 but it decreased in the samples containing higher amounts of reinforcement.
文摘γ-Fe nano-particles with size of 20-40 nm were produced by SF6-sensitized CW CO2 laser-induced gaseous pyrolysis of Fe(Co) 5, The γ-Fe stabte in reaction zone at above 910℃ was formed.The rapid quenching prevents from the γ-Fe transforming to α-Fe as rapidly cooling from high temperature to room temperature, The characteristics of the particles were examined at room temperature by TEM. electron diffraction and XRD. It was proved that about 70% of γ-Fe phase in the particles was present. In addition. the lattice constant of the γ-Fe was 0.364 nm in place of 0.360 nm
文摘A S 2O 2- 8/ZrO 2 Al 2O 3 type solid superacid catalyst was prepared from ZrOCl 2·8H 2O, AlCl 3· 6H 2O and (NH 4) 2S 2O 8 by coprecipitation, maceration and calcination processes. Their crystal structures and acidities were determined by XRD and Hammett method, respectively. The activity of the catalyst was studied as function of Al 2O 3 content, calcination temperature and time in the esterification of acetic acid with butanol, and a conversion of 96 5% was obtained. The catalyst gave also higher yields in syntheses of ketals and acetals: cyclohexanone ethylene ketal(86 2%), acetophenone ethylene ketal(78 5%), acetylacetic ester ketal(88 5%), benzaldehyde glycol acetal(76 3%). The chemical structures of the products were confirmed by IR spectra.
文摘以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。
