The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precip...The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60% by CIP under 300 MPa. Then, an ITO target with a relative density larger than 99.6% was obtained by sintering this green compact at 1550℃ for 8 h. The effects of forming pressure, sintering temperature and sintering time on the density of the target were inves- tigated. Also, a discussion was made on the sintering atmosphere.展开更多
Spherical indium tin oxide (ITO) nanoparticles were synthesized by combustion method using citric acid as fuel and nitrates as oxidizer. The obtained ITO nanoparticles were characterized by TG-DSC, FT-IR, XRD, BET, ...Spherical indium tin oxide (ITO) nanoparticles were synthesized by combustion method using citric acid as fuel and nitrates as oxidizer. The obtained ITO nanoparticles were characterized by TG-DSC, FT-IR, XRD, BET, TEM, and SEM. The ITO nanoparticles grew steadily with the increase of heat treatment temperature, and the 700~C calcined particles had a crystallite size of 25.3 nm and a specific surface area of 26.1 m2.g i The avoidance of chlorine ions in the synthesis process decreases particle agglomeration and promotes powder densification. The 900~C sintered pellet had a density of 67.6% of theoretical density (TD) and increased steadily to 97.3% for the 1400℃ sintered ceramics, respectively.展开更多
Two kinds of indium-tin oxide (ITO) precursors, cubic indium hydroxide(In(OH)_3) and orthorhombic indium oxide hydroxide (InOOH), were prepared by a co-precipitationmethod. With the help of X-ray diffraction (XRD), th...Two kinds of indium-tin oxide (ITO) precursors, cubic indium hydroxide(In(OH)_3) and orthorhombic indium oxide hydroxide (InOOH), were prepared by a co-precipitationmethod. With the help of X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and differentialthermal analysis (DTA), phase evolutions from cubic In(OH)_3 and orthorhombic InOOH to cubic ITOsolid solution and rhombohedral ITO solid solution by heat-treatment had been comprehensivelyinvestigated. The transformation from cubic In(OH)_3 to cubic ITO solid solution started as low as150 deg C and ended at about 300 degC, and it exhibited an endothermic behavior. The transformationfrom orthorhombic InOOH to rhombohedral ITO solid solution started at 220 deg C and ended at about430 deg C. Moreover, this transformation was composed of two processes: the one was the dehydrationof InOOH exhibiting an endothermic behavior and the other was the transformation from dehydrationproducts to rhombohedral ITO solid solution exhibiting a strong exothermic behavior. RhombohedralITO solid solution was metastable in air and it would transform to cubic ITO solid solution byheat-treatment. The transformation from rhombohedral ITO solid solution to cubic ITO solid solutionstarted at 578 deg C and ended below 800 deg C, and it exhibited a weak exothermic behavior.展开更多
Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO_2) and heavy metal oxide (M_2O_3) respectively were fabricated from glass powders. After sintering and crystallizati...Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO_2) and heavy metal oxide (M_2O_3) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results show that the additives both heavy metal oxide and rare earth oxide promote the sintering and lower the phase temperature from μ- to α-cordierite as well as affect the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples is as low as 900 ℃. The materials have a low dielectric constant (≈5), a low thermal expansion coefficient ((2.80~3.52)×10^(-6) ℃^(-1)) and a low dissipation factor (≤0.2%) and can be co-fired with high conductivity metals such as Au, Cu, Ag/Pd paste at low temperature (below 950 ℃), which makes it to be a promising material for low-temperature co-fired ceramic substrates.展开更多
Transparent conductive indium tin oxide (ITO) nanoparticles were synthesized by a novel sol-gel method. Granulated indium and tin were dissolved in HNO3 and partially complexed with citric acid. A sol-gel process wa...Transparent conductive indium tin oxide (ITO) nanoparticles were synthesized by a novel sol-gel method. Granulated indium and tin were dissolved in HNO3 and partially complexed with citric acid. A sol-gel process was induced when tertiary butyl alcohol was added dropwise to the above solution. ITO nanopartides with an average crystallite size of 18.5 nm and surface area of 32.6 m^2 ]g were obtained after the gel was heat-treated at 700 ℃, The ITO nanoparticles showed good sinterability, the starting sintering temperature decreased sharply to 900 ℃, and the 1400 ℃ sintered pellet had a density of 98.1% of theoretical density (TD).展开更多
Three-dimensional (3D) ordered macroporous indium tin oxide (ITO) is pre- pared using a polymer colloidal crystal template that is formed by self-assembly of the monodisperse poly(methyl methacrylate) (PMMA) microsphe...Three-dimensional (3D) ordered macroporous indium tin oxide (ITO) is pre- pared using a polymer colloidal crystal template that is formed by self-assembly of the monodisperse poly(methyl methacrylate) (PMMA) microspheres. The morphologies and BET surface area of the macroporous material is examined by scanning electron micro- scope, transmission electron microscopy and N2 adsorption/desorption. Results indicate that the macroporous material has highly ordered arrays of the uniform pores replicated from the PMMA colloidal crystal template when the polymer colloidal crystal template is removed by calcinations at 500℃. The pore diameter (about 450 nm) of macroporous ITO slightly shrank to the PMMA microspheres. The BET surface area and pore volume of the macroporous material are 389 m2·g-1 and 0.36 cm3·g-1, respectively. Moreover, the macroporous ITO, containing 5 mol% Sn and after annealing under vacuum, shows the minimum resistivity of ρ = 8.2×10-3 Ω· cm. The conductive mechanism of macroporous ITO is discussed, and it is believed that the oxygen vacancies are the major factor for excellent electrical properties.展开更多
基金supported by the National High-Tech Research and Development Program of China(No. 2004AA303542)
文摘The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60% by CIP under 300 MPa. Then, an ITO target with a relative density larger than 99.6% was obtained by sintering this green compact at 1550℃ for 8 h. The effects of forming pressure, sintering temperature and sintering time on the density of the target were inves- tigated. Also, a discussion was made on the sintering atmosphere.
文摘Spherical indium tin oxide (ITO) nanoparticles were synthesized by combustion method using citric acid as fuel and nitrates as oxidizer. The obtained ITO nanoparticles were characterized by TG-DSC, FT-IR, XRD, BET, TEM, and SEM. The ITO nanoparticles grew steadily with the increase of heat treatment temperature, and the 700~C calcined particles had a crystallite size of 25.3 nm and a specific surface area of 26.1 m2.g i The avoidance of chlorine ions in the synthesis process decreases particle agglomeration and promotes powder densification. The 900~C sintered pellet had a density of 67.6% of theoretical density (TD) and increased steadily to 97.3% for the 1400℃ sintered ceramics, respectively.
文摘Two kinds of indium-tin oxide (ITO) precursors, cubic indium hydroxide(In(OH)_3) and orthorhombic indium oxide hydroxide (InOOH), were prepared by a co-precipitationmethod. With the help of X-ray diffraction (XRD), thermo-gravimetric analysis (TGA) and differentialthermal analysis (DTA), phase evolutions from cubic In(OH)_3 and orthorhombic InOOH to cubic ITOsolid solution and rhombohedral ITO solid solution by heat-treatment had been comprehensivelyinvestigated. The transformation from cubic In(OH)_3 to cubic ITO solid solution started as low as150 deg C and ended at about 300 degC, and it exhibited an endothermic behavior. The transformationfrom orthorhombic InOOH to rhombohedral ITO solid solution started at 220 deg C and ended at about430 deg C. Moreover, this transformation was composed of two processes: the one was the dehydrationof InOOH exhibiting an endothermic behavior and the other was the transformation from dehydrationproducts to rhombohedral ITO solid solution exhibiting a strong exothermic behavior. RhombohedralITO solid solution was metastable in air and it would transform to cubic ITO solid solution byheat-treatment. The transformation from rhombohedral ITO solid solution to cubic ITO solid solutionstarted at 578 deg C and ended below 800 deg C, and it exhibited a weak exothermic behavior.
文摘Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO_2) and heavy metal oxide (M_2O_3) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results show that the additives both heavy metal oxide and rare earth oxide promote the sintering and lower the phase temperature from μ- to α-cordierite as well as affect the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples is as low as 900 ℃. The materials have a low dielectric constant (≈5), a low thermal expansion coefficient ((2.80~3.52)×10^(-6) ℃^(-1)) and a low dissipation factor (≤0.2%) and can be co-fired with high conductivity metals such as Au, Cu, Ag/Pd paste at low temperature (below 950 ℃), which makes it to be a promising material for low-temperature co-fired ceramic substrates.
基金supported by grants from Ph.D. Programs Foundation of Ministry of Education of China (200802511022)National Natural Science Foundation of China (50902049)
文摘Transparent conductive indium tin oxide (ITO) nanoparticles were synthesized by a novel sol-gel method. Granulated indium and tin were dissolved in HNO3 and partially complexed with citric acid. A sol-gel process was induced when tertiary butyl alcohol was added dropwise to the above solution. ITO nanopartides with an average crystallite size of 18.5 nm and surface area of 32.6 m^2 ]g were obtained after the gel was heat-treated at 700 ℃, The ITO nanoparticles showed good sinterability, the starting sintering temperature decreased sharply to 900 ℃, and the 1400 ℃ sintered pellet had a density of 98.1% of theoretical density (TD).
文摘Three-dimensional (3D) ordered macroporous indium tin oxide (ITO) is pre- pared using a polymer colloidal crystal template that is formed by self-assembly of the monodisperse poly(methyl methacrylate) (PMMA) microspheres. The morphologies and BET surface area of the macroporous material is examined by scanning electron micro- scope, transmission electron microscopy and N2 adsorption/desorption. Results indicate that the macroporous material has highly ordered arrays of the uniform pores replicated from the PMMA colloidal crystal template when the polymer colloidal crystal template is removed by calcinations at 500℃. The pore diameter (about 450 nm) of macroporous ITO slightly shrank to the PMMA microspheres. The BET surface area and pore volume of the macroporous material are 389 m2·g-1 and 0.36 cm3·g-1, respectively. Moreover, the macroporous ITO, containing 5 mol% Sn and after annealing under vacuum, shows the minimum resistivity of ρ = 8.2×10-3 Ω· cm. The conductive mechanism of macroporous ITO is discussed, and it is believed that the oxygen vacancies are the major factor for excellent electrical properties.