The electrical and optical effects of particles on the nano aluminum film deposited by thermal evaporation was investigated. From the characterization results of scanning electron microscope（SEM）, the accumulation i...The electrical and optical effects of particles on the nano aluminum film deposited by thermal evaporation was investigated. From the characterization results of scanning electron microscope（SEM）, the accumulation in tens of nanometers had been observed. The current-voltage（I-V） curve of the sample indicates its nonlinear electrical characters expecting the corresponding nonlinear optical properties. By the theoretical calculation, nonlinear conduction of the carrier transportation may result from the barrier-well-barrier structure, where negative resistance and Coulomb blockade effect appears. The simulation results are approximately matched with the experimental results. By testing the fluorescence emission spectrum of the sample, peaks were found to be located at 420 and 440 nm. In addition, the full width at half maximum（FWHM） had been obviously broadened by means of adding 2, 5-diphenyloxazole（DPO）. Therefore, discrete energy levels could be estimated inside those particles.展开更多
Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity ...Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity and functionality of the novel energetic nanocomposites are still limited.In this work,spray crystallization(SC)method was used to prepare novel energetic nanocomposites,the high-energy metal-organic complex[Ni(CHZ)_(3)](ClO_(4))_(2)(CHZ=1,3-diaminourea)was composited with nanoaluminum(n-Al).Results showed that n-Al/[Ni(CH_(2))_(3)](ClO_(4))_(2)energetic nanocomposites prepared by SC method increased heat release to 2977.6 J/g and peak pressure to 3.91 MPa with higher pressurization rate(1324.06 MPa/s),decreased sensitivity thresholds(>100 mJ)to electrostatic discharge(ESD)and enhanced detonation ability compared with[Ni(CHZ)_(3)](ClO_(4))_(2)alone and physically mixed(PM)n-Al/[Ni(CHZ)_(3)](ClO_(4))_(2).These results proved that it is significant to introduce energetic metal-organic complexes with inherent high energy in new-concept n-Al/energetic metal-organic complexes nanocomposites through SC method for a better performance of its application.展开更多
The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds o...The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.展开更多
Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scann...Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.展开更多
Recently, more and more interest has been focused on zirconia and its characteristics. In this paper, aluminum can be successfully incorporated into nano-ZrO2 via a cationic surfactant assisted route in the earlier pr...Recently, more and more interest has been focused on zirconia and its characteristics. In this paper, aluminum can be successfully incorporated into nano-ZrO2 via a cationic surfactant assisted route in the earlier preparation procedure. XRD, TEM, EDS, Uv-vis and N2 adsorption-desorption analysis methods were adopted for the characterization of prepared samples. The results show that aluminum has been homogeneously incorporated into nano-ZrO2. The prepared aluminum-doped samples show a distinctive blue shift in the Uv-vis spectra compared to normal nano-ZrO2. The distinctive increase of thermal stability and a mesoporous structure were observed.展开更多
The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as ...The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20～50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal.展开更多
Ammonium aluminum carbonate hydroxide (AACH) was synthesized by the reaction of ammonium aluminum sulphate (AA) with ammonium hydrogen carbonate (AHC). AA was obtained by the reaction of NH4HSO4 with aluminum scraps a...Ammonium aluminum carbonate hydroxide (AACH) was synthesized by the reaction of ammonium aluminum sulphate (AA) with ammonium hydrogen carbonate (AHC). AA was obtained by the reaction of NH4HSO4 with aluminum scraps as the raw materials. According to this method, AACH samples prepared were used to fabricate nano alumina powders by thermal decomposition. The microstructural properties of as-formed alumina were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), special surface analysis and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Experimental observations revealed that highly pure (99.99%) α-alumina with mean diameter of 49 nm could be obtained.展开更多
The paper presents the results of studies surface microrelief, frequency-temperature characteristics of the imaginary part of the dielectric permittivity and dielectric loss of PE+TlInSe2 composite materials in 25。C ...The paper presents the results of studies surface microrelief, frequency-temperature characteristics of the imaginary part of the dielectric permittivity and dielectric loss of PE+TlInSe2 composite materials in 25。C - 150。C temperature and 25 Hz - 1 MHz frequency range before and after application of the aluminum nano-particles with a size of 50 nm. The change in the amount of semicon-ductor filler TlInSe2 and aluminum nano-particles changes the state of the surface and the frequency-temperature characteristics of composite materials PE+xvol.%TlInSe2, which allows to obtain composites with the desired dielectric permittivity and dielectric loss.展开更多
基金Supported by the 973 Program(No.2014CB932103)the 863 Program(No.2013AA032501)the National Natural Science Foundation of China(NSFC No.21676015)
文摘The electrical and optical effects of particles on the nano aluminum film deposited by thermal evaporation was investigated. From the characterization results of scanning electron microscope（SEM）, the accumulation in tens of nanometers had been observed. The current-voltage（I-V） curve of the sample indicates its nonlinear electrical characters expecting the corresponding nonlinear optical properties. By the theoretical calculation, nonlinear conduction of the carrier transportation may result from the barrier-well-barrier structure, where negative resistance and Coulomb blockade effect appears. The simulation results are approximately matched with the experimental results. By testing the fluorescence emission spectrum of the sample, peaks were found to be located at 420 and 440 nm. In addition, the full width at half maximum（FWHM） had been obviously broadened by means of adding 2, 5-diphenyloxazole（DPO）. Therefore, discrete energy levels could be estimated inside those particles.
基金supported by National Natural Science Foundation of China(project no.51676100)。
文摘Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity and functionality of the novel energetic nanocomposites are still limited.In this work,spray crystallization(SC)method was used to prepare novel energetic nanocomposites,the high-energy metal-organic complex[Ni(CHZ)_(3)](ClO_(4))_(2)(CHZ=1,3-diaminourea)was composited with nanoaluminum(n-Al).Results showed that n-Al/[Ni(CH_(2))_(3)](ClO_(4))_(2)energetic nanocomposites prepared by SC method increased heat release to 2977.6 J/g and peak pressure to 3.91 MPa with higher pressurization rate(1324.06 MPa/s),decreased sensitivity thresholds(>100 mJ)to electrostatic discharge(ESD)and enhanced detonation ability compared with[Ni(CHZ)_(3)](ClO_(4))_(2)alone and physically mixed(PM)n-Al/[Ni(CHZ)_(3)](ClO_(4))_(2).These results proved that it is significant to introduce energetic metal-organic complexes with inherent high energy in new-concept n-Al/energetic metal-organic complexes nanocomposites through SC method for a better performance of its application.
文摘The influence of the precipitating reagents and dispersants on the formation of nano-aluminum hydroxide from sodium aluminate solution by chemical precipitation was investigated. The influence of the dispersed seeds on the decomposi-tion process was investigated too. The alkaline aluminate solutions were used as original solutions with a concentration of Al2O3 having 14.78 g/dm3, αk—1.6 and127 g/dm3, αk—1.6. For the precipitation processes there were used follow-ing precipitating reagents—solutions HCl, NaHCO3 and NH4HCO3 with a concentration of 80 g/dm3, dispersants—PEG 6000, (NaPO3)6 and Tween 20. For the decomposition process the dispersed seeds and factories seeds were used. Structural studies of the aluminum hydroxide particles were carried out by means of the electron-probe microanalysis and scanning electron microscopy, and phase composition of products was determined by means of X-ray diffraction analysis. Ammonium bicarbonate and Tween 20 were determined as the optimal precipitating reagent and dispersant, correspondingly, resulting in dispersed aluminum hydroxide, which is used as a seed in the decomposition process. It was established that this product in form of dispersed seed considerably reduces the duration of the decomposition process;the maximal decomposition of solution (73.9%) was observed after injection of dispersеd aluminum hydroxide into solution. The final aluminum hydroxide having 90% of particles less than 100 nanometers was obtained within 7 hours of steady decreasing temperature from 70°C to 48°C.
文摘Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.
基金This is a key project of high and new science and technology and supported by Science & Technology Department of Fujian Province (2004H008)
文摘Recently, more and more interest has been focused on zirconia and its characteristics. In this paper, aluminum can be successfully incorporated into nano-ZrO2 via a cationic surfactant assisted route in the earlier preparation procedure. XRD, TEM, EDS, Uv-vis and N2 adsorption-desorption analysis methods were adopted for the characterization of prepared samples. The results show that aluminum has been homogeneously incorporated into nano-ZrO2. The prepared aluminum-doped samples show a distinctive blue shift in the Uv-vis spectra compared to normal nano-ZrO2. The distinctive increase of thermal stability and a mesoporous structure were observed.
文摘The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20～50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal.
基金the National Natural Science Foundation of China (NSFC 20503015)
文摘Ammonium aluminum carbonate hydroxide (AACH) was synthesized by the reaction of ammonium aluminum sulphate (AA) with ammonium hydrogen carbonate (AHC). AA was obtained by the reaction of NH4HSO4 with aluminum scraps as the raw materials. According to this method, AACH samples prepared were used to fabricate nano alumina powders by thermal decomposition. The microstructural properties of as-formed alumina were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), special surface analysis and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Experimental observations revealed that highly pure (99.99%) α-alumina with mean diameter of 49 nm could be obtained.
文摘The paper presents the results of studies surface microrelief, frequency-temperature characteristics of the imaginary part of the dielectric permittivity and dielectric loss of PE+TlInSe2 composite materials in 25。C - 150。C temperature and 25 Hz - 1 MHz frequency range before and after application of the aluminum nano-particles with a size of 50 nm. The change in the amount of semicon-ductor filler TlInSe2 and aluminum nano-particles changes the state of the surface and the frequency-temperature characteristics of composite materials PE+xvol.%TlInSe2, which allows to obtain composites with the desired dielectric permittivity and dielectric loss.
