Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 ...Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.展开更多
Bi26MO10O69 nanopowder was prepared by hydrothermal method and used as a surface modification material for oxygen separation membrane to enhance oxygen permeability. Thermal decomposition behavior and phase variation ...Bi26MO10O69 nanopowder was prepared by hydrothermal method and used as a surface modification material for oxygen separation membrane to enhance oxygen permeability. Thermal decomposition behavior and phase variation of the precursor were investigated by thermal analyzer （TG-DSC） and high-temperature X-ray diffraction （HT-XRD）. Bi26MO10O69 porous layer was coated on the air side of BaCo0.7Fe0.2Nb0.1O3-δ （BCFN） oxygen permeable membrane by dipping method. In the partial oxidation experiment of coke oven gas （COG）, the Bi26Mo10O69-coated BCFN membrane exhibits higher oxygen permeability and CH4 conversion than the uncoated BCFN membrane. When the thickness of BCFN membrane was 1 mm and the COG and air fluxes were 120 and 100 mL/min, the oxygen permeation flux reached 16.48 mL/（min.cm^2） at 875℃, which was 16.96% higher than the uncoated BCFN membrane. Therefore, Bi26MoloO69 porous layer on the air side will be promising modification coating on the oxygen permeability of BCFN membrane.展开更多
基金Projects(5110205551462005)supported by the National Natural Science Foundation of China
文摘Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.
基金Projects(51272154,51472156)supported by the National Natural Science Foundation of ChinaProjects(sdcx2012033,sdcx2012062)supported by the Innovation Fund of Shanghai University,China+1 种基金Project(14ZR1416400)supported by Special Research Foundation for Training and Selecting Outstanding Young Teachers of Universities in Shanghai,Chinasupported by Shanghai Science and Technology Committee,China
文摘Bi26MO10O69 nanopowder was prepared by hydrothermal method and used as a surface modification material for oxygen separation membrane to enhance oxygen permeability. Thermal decomposition behavior and phase variation of the precursor were investigated by thermal analyzer （TG-DSC） and high-temperature X-ray diffraction （HT-XRD）. Bi26MO10O69 porous layer was coated on the air side of BaCo0.7Fe0.2Nb0.1O3-δ （BCFN） oxygen permeable membrane by dipping method. In the partial oxidation experiment of coke oven gas （COG）, the Bi26Mo10O69-coated BCFN membrane exhibits higher oxygen permeability and CH4 conversion than the uncoated BCFN membrane. When the thickness of BCFN membrane was 1 mm and the COG and air fluxes were 120 and 100 mL/min, the oxygen permeation flux reached 16.48 mL/（min.cm^2） at 875℃, which was 16.96% higher than the uncoated BCFN membrane. Therefore, Bi26MoloO69 porous layer on the air side will be promising modification coating on the oxygen permeability of BCFN membrane.
