Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine cer...Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.展开更多
Metal and nano-ceramic nanocomposite coatings were prepared on the gray cast iron surface by the electrodeposition method. The Ni-Co was used as the metal matrix,and nano-Al2O3 was chosen as the second-phase particula...Metal and nano-ceramic nanocomposite coatings were prepared on the gray cast iron surface by the electrodeposition method. The Ni-Co was used as the metal matrix,and nano-Al2O3 was chosen as the second-phase particulates. To avoid poor inter-face bonding and stress distribution,the gradient structure of biology materials was found as the model and therefore the gradient composite coating was prepared. The morphology of the composite coatings was flatter and the microstructure was denser than that of pure Ni-Co coatings. The composite coatings were prepared by different current densities,and the 2-D and 3-D morphologies of the surface coatings were observed. The result indicated that the 2-D structure became rougher and the 3-D surface density of apices became less when the current density was increased. The content of nanoparticulates reached a maximum value at the current density of 40mA·cm^-2,at the same time the properties including microhardness and wear-resistance were analyzed. The microhardness reached a maximum value and the wear volume was also less at the current density of 40mA·cm^-2. The reason was that nano-Al2O3 particles caused dispersive strengthening and grain refining.展开更多
A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction...A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction （ XRD ） pattern indicates that the products were a composite with both of anatase-type TiO2 and tetrahedrul SnO2. The prnducts were also characterized by transmission electron microscolry （ TEM ）, photoluminescence （PL） spectra. The photo-catalytic property of the as-prepared sample has ulso been studied. The result indicates that the as-prepared sample is a good photo-catadyst.展开更多
Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 parti...Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 particle (Al2O3np) reinforced B4Cp/Al + Al2O3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al2O3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B4Cp/Al composites. The results indicated that the neutron absorption properties of B4Cp/Al composites were not affected by the addition of nano-Al2O3 particles in the range of 1 wt%-15 wt%. The addition of Al2O3np can obviously reduce the grain size of B4Cp/Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al2O3np is about 2.5 wt%. Both B4Cp and Al2O3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important.展开更多
A new kind of nano-biomaterials of nano apatite （ NA ） and polyamide8063 （ PA ） composite was prepared by direct using NA slurry. The experimental results showed that the NA content in the composite was similar to...A new kind of nano-biomaterials of nano apatite （ NA ） and polyamide8063 （ PA ） composite was prepared by direct using NA slurry. The experimental results showed that the NA content in the composite was similar to that of natural bone. Interfrace chemical bonding was formed between NA and PA. The NA keeps the original morphological structure with a crystal size of 10- 30 nm in width by 50- 90 nm in length with a ratio of - 2.5 and distributed uniformly in thepolymer. The synthetic nano-biomaterials could be one of the best bioactive materials for load-bearing bone repair or substitution materials.展开更多
A comparative analysis of perovskite structured cathode materials, La0.65Sr0.35Mn03 （LSM）, La0.8Sr0.2CoO3 （LSC）, La0.6Sr0.4FeO3 （LSF） and La0.6Sr0.4Co0.2Fe0.803 （LSCF）, was performed for a ceramic-carbonate na...A comparative analysis of perovskite structured cathode materials, La0.65Sr0.35Mn03 （LSM）, La0.8Sr0.2CoO3 （LSC）, La0.6Sr0.4FeO3 （LSF） and La0.6Sr0.4Co0.2Fe0.803 （LSCF）, was performed for a ceramic-carbonate nanocomposite fuel cell using composite electrolyte consisting of Gd0.1Ce0.9O1.95 （GDC） and a eutectic mixture of Na2CO3 and Li2CO3. The compatibility of these nanocomposite electrode powder materials was investigated under air, CO2 and air/CO2 atmospheres at 550 ℃. Microscopy measurements together with energy dispersive X-ray spectroscopy （EDS） elementary analysis revealed few spots with higher counts of manganese relative to lanthanum and strontium under pure CO2 atmosphere. Furthermore, electrochemical impedance （EIS） analysis showed that LSC had the lowest resistance to oxygen reduction reaction （ORR） （14.12 Ω·cm^2） followed by LSF （15.23 Ω·cm^2）, LSCF （19.38Ω·cm^2） and LSM （ 〉 300 Ω·cm^2）. In addition, low frequency EIS measurements （down to 50 gHz） revealed two additional semi-circles at frequencies around 1 Hz. These semicircles can yield additional information about electrochemical reactions in the device. Finally, a fuel cell was fabricated using GDC/NLC nanocomposite electrolyte and its composite with NiO and LSCF as anode and cathode, respectively. The cell produced an excellent power density of 1.06 W/cm^2 at 550 ℃ under fuel cell conditions.展开更多
A novel and simple ion-exchange method was developed for the synthesis of nano-SnO/micro-C hybrid structure. The structure of the as prepared nano-SnO/micro-C was directly revealed by scanning electron microscopy （SE...A novel and simple ion-exchange method was developed for the synthesis of nano-SnO/micro-C hybrid structure. The structure of the as prepared nano-SnO/micro-C was directly revealed by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. SnO particles with the size about 25 nm were well confined in amorphous carbon microparticles. Carbon matrix in micrometer scale not only acts as a protective buffer for the SnO nanoparticles during the battery cycling processes, but also avoids the shortcomings of nanostructures, such as low tap density and potential safety threats. Electrochemical behaviors of the nano-SnO/micro-C were tested as anode material in lithium ion batteries. The initial reversible capacity is 508 mA h g^-1, and the reversible capacity after 60 cycles is 511 mA h g^-1, indicating good capacity retention ability.展开更多
基金Project supported by the National Natural Science Foundation of China (50271010)the Doctorial Foundation of JinanUniversity (B0606)
文摘Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.
基金the National Natural Science Foundation of China (No50635030)the National Basic Research of China (No2007CB616913)the Program for New Century Excellent Talents in University (2005)
文摘Metal and nano-ceramic nanocomposite coatings were prepared on the gray cast iron surface by the electrodeposition method. The Ni-Co was used as the metal matrix,and nano-Al2O3 was chosen as the second-phase particulates. To avoid poor inter-face bonding and stress distribution,the gradient structure of biology materials was found as the model and therefore the gradient composite coating was prepared. The morphology of the composite coatings was flatter and the microstructure was denser than that of pure Ni-Co coatings. The composite coatings were prepared by different current densities,and the 2-D and 3-D morphologies of the surface coatings were observed. The result indicated that the 2-D structure became rougher and the 3-D surface density of apices became less when the current density was increased. The content of nanoparticulates reached a maximum value at the current density of 40mA·cm^-2,at the same time the properties including microhardness and wear-resistance were analyzed. The microhardness reached a maximum value and the wear volume was also less at the current density of 40mA·cm^-2. The reason was that nano-Al2O3 particles caused dispersive strengthening and grain refining.
文摘A microwave-assisted heating approach was developed to fabricate SnO2·TiO2 nano-composite in an aqueoas sohaion of sulphuric acid in the presence of SnO2 nano-powder and titanium sulfate. Powder X-ray diffraction （ XRD ） pattern indicates that the products were a composite with both of anatase-type TiO2 and tetrahedrul SnO2. The prnducts were also characterized by transmission electron microscolry （ TEM ）, photoluminescence （PL） spectra. The photo-catalytic property of the as-prepared sample has ulso been studied. The result indicates that the as-prepared sample is a good photo-catadyst.
基金Funded by Natural National Science Foundation of China(NSFC)(No.11305149)National High-Tech R&D Program(863 Program)(No.2013AA030704)。
文摘Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 particle (Al2O3np) reinforced B4Cp/Al + Al2O3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al2O3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B4Cp/Al composites. The results indicated that the neutron absorption properties of B4Cp/Al composites were not affected by the addition of nano-Al2O3 particles in the range of 1 wt%-15 wt%. The addition of Al2O3np can obviously reduce the grain size of B4Cp/Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al2O3np is about 2.5 wt%. Both B4Cp and Al2O3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important.
文摘A new kind of nano-biomaterials of nano apatite （ NA ） and polyamide8063 （ PA ） composite was prepared by direct using NA slurry. The experimental results showed that the NA content in the composite was similar to that of natural bone. Interfrace chemical bonding was formed between NA and PA. The NA keeps the original morphological structure with a crystal size of 10- 30 nm in width by 50- 90 nm in length with a ratio of - 2.5 and distributed uniformly in thepolymer. The synthetic nano-biomaterials could be one of the best bioactive materials for load-bearing bone repair or substitution materials.
文摘A comparative analysis of perovskite structured cathode materials, La0.65Sr0.35Mn03 （LSM）, La0.8Sr0.2CoO3 （LSC）, La0.6Sr0.4FeO3 （LSF） and La0.6Sr0.4Co0.2Fe0.803 （LSCF）, was performed for a ceramic-carbonate nanocomposite fuel cell using composite electrolyte consisting of Gd0.1Ce0.9O1.95 （GDC） and a eutectic mixture of Na2CO3 and Li2CO3. The compatibility of these nanocomposite electrode powder materials was investigated under air, CO2 and air/CO2 atmospheres at 550 ℃. Microscopy measurements together with energy dispersive X-ray spectroscopy （EDS） elementary analysis revealed few spots with higher counts of manganese relative to lanthanum and strontium under pure CO2 atmosphere. Furthermore, electrochemical impedance （EIS） analysis showed that LSC had the lowest resistance to oxygen reduction reaction （ORR） （14.12 Ω·cm^2） followed by LSF （15.23 Ω·cm^2）, LSCF （19.38Ω·cm^2） and LSM （ 〉 300 Ω·cm^2）. In addition, low frequency EIS measurements （down to 50 gHz） revealed two additional semi-circles at frequencies around 1 Hz. These semicircles can yield additional information about electrochemical reactions in the device. Finally, a fuel cell was fabricated using GDC/NLC nanocomposite electrolyte and its composite with NiO and LSCF as anode and cathode, respectively. The cell produced an excellent power density of 1.06 W/cm^2 at 550 ℃ under fuel cell conditions.
基金supported by the National Natural Science Foundation of China(No.51001098)the Natural Science Foundation of Liaoning Province(No.20102229)+1 种基金the Institute of Metal Research(No.09NBA211A1)the National Basic Research Program(973 Program,No.2011CBA00504)
文摘A novel and simple ion-exchange method was developed for the synthesis of nano-SnO/micro-C hybrid structure. The structure of the as prepared nano-SnO/micro-C was directly revealed by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. SnO particles with the size about 25 nm were well confined in amorphous carbon microparticles. Carbon matrix in micrometer scale not only acts as a protective buffer for the SnO nanoparticles during the battery cycling processes, but also avoids the shortcomings of nanostructures, such as low tap density and potential safety threats. Electrochemical behaviors of the nano-SnO/micro-C were tested as anode material in lithium ion batteries. The initial reversible capacity is 508 mA h g^-1, and the reversible capacity after 60 cycles is 511 mA h g^-1, indicating good capacity retention ability.
