Homogeneous, crack-free SrNbxTi1-xO3 thin films on （110） silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr（OAc）2 glacial a...Homogeneous, crack-free SrNbxTi1-xO3 thin films on （110） silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr（OAc）2 glacial acetic acid solution, after being refluxed and reacted with tartrate, formed Sr（OAc）2（C4H6O6）2; Ti（OBu）4 formed Ti（OAc）4-x（AcAc）x. after having the ligand partially exchanged with AcAc, while Nb（OC2H5）5 formed （OAc）2Nb（AcAc） （C4H606）by exchanging of ligand in glacial acetic acid with （CH3CO）2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNb,Ti1-xO3 cluster sol. Methyl cellulose （MCL） caused SrNbxTi1-xO3 sol to have polymeric structure and easily form films. SrNbxTi1-xO3 films with perovskite were subsequently formed after being annealed at 650-750 ℃ for 60 min in 25% N2＋75% H2 （volume ratio） atmosphere. Resistivity of the SrNb0.1 Ti0.9O3 films at room temperature was 64 μΩ·cm, a particular T2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed.展开更多
A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the st...A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the starting materials and propylene oxide （PO） as complexing agent at a low temperature. Simultaneously, the experimen- tal and theoretical studies of ZrB2 synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO2 phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400~C in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O sys- tem producing ZrB2 by boro/carbothermal reaction was established based on thermodynamic analysis. It was also ob- served that, with the increase of reaction temperature, the reaction which produced ZrB2 powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.展开更多
To fabricate thick-walled hollow glass microspheres （HGMs） for inertial confinement fusion （ICF） targets by sol-gel technology, we investigated the effects of glass composition, blowing agent, refining temperature...To fabricate thick-walled hollow glass microspheres （HGMs） for inertial confinement fusion （ICF） targets by sol-gel technology, we investigated the effects of glass composition, blowing agent, refining temperature, pressure and composition of furnace atmosphere on the wall thickness of HGMs by numerical simulation and experiments. The results showed that the residence times of the thick-walled HGMs in the encapsulating and refining phases decreased with the increase of wall thickness of HGMs. As a response to this challenge, glass composition must be optimized with the object of high surface tension and low viscosity at refining temperature, and the blowing agents with high decomposition temperature should be used, furthermore the concentration of blowing agents in gel particles must also be precisely controlled. The higher volume fraction of argon gas in the furnace atmosphere, the thicker the wall of HGMs. Due to the limited operating range of furnace atmosphere pressure, changing furnace atmosphere pressure could not significantly increase the wall thickness of HGMs. Although increasing refin- ing temperature can improve the yield of high quality HGMs, a higher furnace atmosphere temperature may lead to a decrease in the wall thickness of HGMs. When the volume fraction of argon gas in the furnace atmosphere ranged from 80% to 95%, the furnace atmosphere pressure ranged from 1.0×l0^5 Pa to 1.25×105 Pa, and the refining temperature ranged from 1600℃ to 1800℃, we produced thick-walled （5-10 ktrn） HGMs with good sphericity, wall thickness uniformity and surface finish. However, the yield of high quality HGMs needs to be further improved. The compressive strength, tensile strength and permeation coefficient to deuterium gas of thick-walled HGMs at ambient temperature decreased with increase of the wall thickness.展开更多
基金Project (No. 2002CB613305) supported by the National Basic Re-search Program (973) of China
文摘Homogeneous, crack-free SrNbxTi1-xO3 thin films on （110） silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr（OAc）2 glacial acetic acid solution, after being refluxed and reacted with tartrate, formed Sr（OAc）2（C4H6O6）2; Ti（OBu）4 formed Ti（OAc）4-x（AcAc）x. after having the ligand partially exchanged with AcAc, while Nb（OC2H5）5 formed （OAc）2Nb（AcAc） （C4H606）by exchanging of ligand in glacial acetic acid with （CH3CO）2O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNb,Ti1-xO3 cluster sol. Methyl cellulose （MCL） caused SrNbxTi1-xO3 sol to have polymeric structure and easily form films. SrNbxTi1-xO3 films with perovskite were subsequently formed after being annealed at 650-750 ℃ for 60 min in 25% N2＋75% H2 （volume ratio） atmosphere. Resistivity of the SrNb0.1 Ti0.9O3 films at room temperature was 64 μΩ·cm, a particular T2 temperature dependence of the resistivity, from 25 K up to room temperature, was observed.
基金Supported by the Fund for the Self-dependent Innovation of Tianjin University(2014)
文摘A single phase of zirconium diboride （ZrB2） powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride （ZrOC12 ~ 8H20）, nano-scale boron and suerose（C12H22011）as the starting materials and propylene oxide （PO） as complexing agent at a low temperature. Simultaneously, the experimen- tal and theoretical studies of ZrB2 synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO2 phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400~C in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O sys- tem producing ZrB2 by boro/carbothermal reaction was established based on thermodynamic analysis. It was also ob- served that, with the increase of reaction temperature, the reaction which produced ZrB2 powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.
基金supported by the Chinese Key Laboratory of Science and Technology for Defense(Grant No.91400C680603090C68)
文摘To fabricate thick-walled hollow glass microspheres （HGMs） for inertial confinement fusion （ICF） targets by sol-gel technology, we investigated the effects of glass composition, blowing agent, refining temperature, pressure and composition of furnace atmosphere on the wall thickness of HGMs by numerical simulation and experiments. The results showed that the residence times of the thick-walled HGMs in the encapsulating and refining phases decreased with the increase of wall thickness of HGMs. As a response to this challenge, glass composition must be optimized with the object of high surface tension and low viscosity at refining temperature, and the blowing agents with high decomposition temperature should be used, furthermore the concentration of blowing agents in gel particles must also be precisely controlled. The higher volume fraction of argon gas in the furnace atmosphere, the thicker the wall of HGMs. Due to the limited operating range of furnace atmosphere pressure, changing furnace atmosphere pressure could not significantly increase the wall thickness of HGMs. Although increasing refin- ing temperature can improve the yield of high quality HGMs, a higher furnace atmosphere temperature may lead to a decrease in the wall thickness of HGMs. When the volume fraction of argon gas in the furnace atmosphere ranged from 80% to 95%, the furnace atmosphere pressure ranged from 1.0×l0^5 Pa to 1.25×105 Pa, and the refining temperature ranged from 1600℃ to 1800℃, we produced thick-walled （5-10 ktrn） HGMs with good sphericity, wall thickness uniformity and surface finish. However, the yield of high quality HGMs needs to be further improved. The compressive strength, tensile strength and permeation coefficient to deuterium gas of thick-walled HGMs at ambient temperature decreased with increase of the wall thickness.
