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
Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmi...Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.展开更多
TiC, ZrC and TaC modified layers were in-situ prepared on graphite matrix by chemical vapor infiltration method with metal salts as the activator. Taking the TiC modified layer as an example, through thermodynamic cal...TiC, ZrC and TaC modified layers were in-situ prepared on graphite matrix by chemical vapor infiltration method with metal salts as the activator. Taking the TiC modified layer as an example, through thermodynamic calculation and experiment, the thermal decomposition process of raw materials(Ti/K_(2)TiF_(6)) was analyzed, the formation mechanism of TiC was determined, and the distribution of TiC modified layer was modulated. The results show that activator K_(2)TiF_(6)has higher decomposition temperature than NH4Cl, which is conducive to improving the utilization rate of raw materials in the gas infiltration process. Increasing the content of Ti powder can increase the concentration of reaction gas and contribute to the formation of TiC modified layer. When the molar ratio of Ti to K_(2)TiF_(6)is 3:1, the surface thickness and infiltration depth of Ti C are 5.42 and 136.24 μm, respectively. Increasing the reaction temperature can improve the rate of in-situ reaction and the thickness of TiC surface layer. When the experimental temperature rises to 1600 °C, the TiC surface layer thickness increases to 20.27 μm.展开更多
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.
文摘Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.
基金financially supported by the National Natural Science Foundation of China(No.11705281)。
文摘TiC, ZrC and TaC modified layers were in-situ prepared on graphite matrix by chemical vapor infiltration method with metal salts as the activator. Taking the TiC modified layer as an example, through thermodynamic calculation and experiment, the thermal decomposition process of raw materials(Ti/K_(2)TiF_(6)) was analyzed, the formation mechanism of TiC was determined, and the distribution of TiC modified layer was modulated. The results show that activator K_(2)TiF_(6)has higher decomposition temperature than NH4Cl, which is conducive to improving the utilization rate of raw materials in the gas infiltration process. Increasing the content of Ti powder can increase the concentration of reaction gas and contribute to the formation of TiC modified layer. When the molar ratio of Ti to K_(2)TiF_(6)is 3:1, the surface thickness and infiltration depth of Ti C are 5.42 and 136.24 μm, respectively. Increasing the reaction temperature can improve the rate of in-situ reaction and the thickness of TiC surface layer. When the experimental temperature rises to 1600 °C, the TiC surface layer thickness increases to 20.27 μm.