In this work,accelerated sintering of Y_(2)O_(3)dispersion strengthened tungsten alloy with a well-regulated structure was achieved by a novel dissolution-precipitation strategy.As indicated,yttrium oxide was firstly ...In this work,accelerated sintering of Y_(2)O_(3)dispersion strengthened tungsten alloy with a well-regulated structure was achieved by a novel dissolution-precipitation strategy.As indicated,yttrium oxide was firstly dissolved into the lattices of W powder precursor during the thermal plasma synthesis process in a one-step and ultra-fast way,and then homogeneously precipitated out within W grains during sintering.The theoretical calculation reveals that the formation process of Y_(2)O_(3)dispersoids enhanced the driving force of densification by increasing the sintering stress and declining the macroscopic viscosity,resulting in improved diffusion ability for the W skeleton.The microstructural investigation further confirmed the occurrence of mass inter-diffusion at the W-Y_(2)O_(3)interface,which provides a fast diffusion pathway for W atoms,and is responsible for the accelerated densification kinetics.Being sintered at 1600°C for 1 h,the as-obtained alloy possesses a high relative density of 98.26%,together with a refined grain size of 970 nm for W and 50 nm for intragranular Y_(2)O_(3),respectively.展开更多
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
基金supported by the National Natural Science Foundation of China(Nos.52130407,52174342)Beijing Natural Science Foundation(No.2232044).
文摘In this work,accelerated sintering of Y_(2)O_(3)dispersion strengthened tungsten alloy with a well-regulated structure was achieved by a novel dissolution-precipitation strategy.As indicated,yttrium oxide was firstly dissolved into the lattices of W powder precursor during the thermal plasma synthesis process in a one-step and ultra-fast way,and then homogeneously precipitated out within W grains during sintering.The theoretical calculation reveals that the formation process of Y_(2)O_(3)dispersoids enhanced the driving force of densification by increasing the sintering stress and declining the macroscopic viscosity,resulting in improved diffusion ability for the W skeleton.The microstructural investigation further confirmed the occurrence of mass inter-diffusion at the W-Y_(2)O_(3)interface,which provides a fast diffusion pathway for W atoms,and is responsible for the accelerated densification kinetics.Being sintered at 1600°C for 1 h,the as-obtained alloy possesses a high relative density of 98.26%,together with a refined grain size of 970 nm for W and 50 nm for intragranular Y_(2)O_(3),respectively.
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.
