The infrared absorption spectrum of zinc oxide whiskers with tetrapod shape was recorded and compared with ZnO powder. The absorptions of microwave and sound were investigated with a result showing that the ZnO whisk...The infrared absorption spectrum of zinc oxide whiskers with tetrapod shape was recorded and compared with ZnO powder. The absorptions of microwave and sound were investigated with a result showing that the ZnO whiskers are of excellence as absorbents of microwave and soundproofing. The results of vibration damping tests of polyvinyl chloride indicate that the material containing the tetrapod shaped ZnO whiskers appears superior damping characteristics.展开更多
Large and uniform tetrapod-like ZnO whiskers （T-ZnO） were prepared from waste hot dipping zinc by vapor oxidation and examined by means of X-ray diffraction and ICP-AES analysis and scanning electron microscope. The...Large and uniform tetrapod-like ZnO whiskers （T-ZnO） were prepared from waste hot dipping zinc by vapor oxidation and examined by means of X-ray diffraction and ICP-AES analysis and scanning electron microscope. The products are pure hexagonal wurtzite crystals with tetrapod shape and edge size of center body 56 μm and needle length of 100130 μm. The size and shape of ZnO particles are fully controlled by the growth conditions and T-ZnO can be obtained only at 8501 000 ℃ and total gas flow rate ranging from 40 to 250 L·h-1 in which the size of the T-ZnO particles varies slightly with temperature. The process of the formation of T-ZnO is that T-ZnO may nucleate at the initial stage with a complete tetrapod shape and develop to the large size, but not the process of （preferential） growth of octahedral nuclei and subsequent growth of the needles. The experiment presents a new method to prepare T-ZnO economically by using the waste hot dipping zinc.展开更多
ZnO whiskers observation on the surface of SnZn/Cu solder joints in concentrator silicon solar cells solder layer is reported. In the experiment,SnZn/Cu samples are left in laboratory after reflow soldering for two ye...ZnO whiskers observation on the surface of SnZn/Cu solder joints in concentrator silicon solar cells solder layer is reported. In the experiment,SnZn/Cu samples are left in laboratory after reflow soldering for two years before an examination by SEM,then ZnO whiskers can be observed obviously,which grows out from the rich-Zn phase of the samples and causes electrical short circuit in the electronics appliances,which demonstrates that the SnZn solder shows a risk for the short circuiting failure of an electronic device. Moreover,the growth mechanism of ZnO whiskers is researched based on cracked oxide theory,which provides the reference support for SnZn solders application.展开更多
Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microsc...Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microscopy,energy dispersive X-ray spectroscopy,and X-ray diffraction techniques were used to study the morphologies and crystal structures of these tetrapod-shaped ZnO microcrystals.The results show that these two types of ZnO tetrapods are grown at different heights within the same crucible.The legs of these tetrapod-shaped ZnO crystals are hexagonally faceted.Some tetrapod-shaped ZnO whiskers show hierarchical structures.A short button-like hexagonal ZnO microcrystal is observed at the triple junctions of some tetrapod-shaped ZnO whiskers.The tetrapod-shaped ZnO microrods are capped by two sets of hexagonal pyramids with two different groups of crystal planes for the surfaces.These two types of tetrapod-shaped ZnO microcrystals have different side faces and aspect ratio,which are believed to be the result of their different growth behaviors.The octa-twin model was used to discuss the different growth behaviors of these two types of ZnO tetrapods.The crystal planes of the legs and the pyramids were determined.展开更多
The influence of Na2 SO4 on the formation of ZnO whiskers was investigated in this paper. ZnO whiskers with aspect ratios of up to 50 were synthesized by dissolving ε-Zn（OH）2 precursor in NaOH/Na2SO4 solution at ro...The influence of Na2 SO4 on the formation of ZnO whiskers was investigated in this paper. ZnO whiskers with aspect ratios of up to 50 were synthesized by dissolving ε-Zn（OH）2 precursor in NaOH/Na2SO4 solution at room temperature, followed by aging of the resulting solution at 140 ℃ for 6 h. Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy analyses revealed that SO4^2- ions were primarily adsorbed on the （1 00） plane of the ZnO whiskers via an outer-sphere com- plex configuration （O-H……O）, thereby promoting the one-dimensional growth of ZnO whiskers along the c-axis.展开更多
Tetrapod-shaped ZnO microcrystals in forms of whiskers and microrods have been grown in the same crucible by thermal evaporation of Zn/C mixtures at a temperature of 930℃ in air without using any catalyst. The tetrap...Tetrapod-shaped ZnO microcrystals in forms of whiskers and microrods have been grown in the same crucible by thermal evaporation of Zn/C mixtures at a temperature of 930℃ in air without using any catalyst. The tetrapod-shaped ZnO microrods were capped by hexagonal pyramids. It is for the first time observed that the tetrapod-shaped ZnO whiskers and microrods have quite different morphologies, and this is believed to be a result of different growth behaviors associated with these two forms of ZnO microcrystals. The octa-twin model has been used to discuss their growth behaviors. Photoluminescence properties of these two forms of tetrapod-shaped ZnO microcrystals have been investigated using different excitation wavelengths. Both of the two forms of ZnO microcrystals showed strong green emission and weak ultraviolet emission behaviors. The excitation spectrum of the tetrapod-shaped ZnO whiskers showed a strong excitation peak at 395 nm, which was not observed for the tetrapod-shaped ZnO microrods.展开更多
文摘The infrared absorption spectrum of zinc oxide whiskers with tetrapod shape was recorded and compared with ZnO powder. The absorptions of microwave and sound were investigated with a result showing that the ZnO whiskers are of excellence as absorbents of microwave and soundproofing. The results of vibration damping tests of polyvinyl chloride indicate that the material containing the tetrapod shaped ZnO whiskers appears superior damping characteristics.
文摘Large and uniform tetrapod-like ZnO whiskers （T-ZnO） were prepared from waste hot dipping zinc by vapor oxidation and examined by means of X-ray diffraction and ICP-AES analysis and scanning electron microscope. The products are pure hexagonal wurtzite crystals with tetrapod shape and edge size of center body 56 μm and needle length of 100130 μm. The size and shape of ZnO particles are fully controlled by the growth conditions and T-ZnO can be obtained only at 8501 000 ℃ and total gas flow rate ranging from 40 to 250 L·h-1 in which the size of the T-ZnO particles varies slightly with temperature. The process of the formation of T-ZnO is that T-ZnO may nucleate at the initial stage with a complete tetrapod shape and develop to the large size, but not the process of （preferential） growth of octahedral nuclei and subsequent growth of the needles. The experiment presents a new method to prepare T-ZnO economically by using the waste hot dipping zinc.
基金Supported by the National Natural Science Foundation of China(No.51475220)State Foundation of Laboratory of Advanced Brazing Filler Metals&Technology(Zhengzhou Research Institute of Mechanical Engineering)(No.SKLABFMT-2015-03)High Level Talent Plan of Jiangsu Normal University(No.YQ2015002)
文摘ZnO whiskers observation on the surface of SnZn/Cu solder joints in concentrator silicon solar cells solder layer is reported. In the experiment,SnZn/Cu samples are left in laboratory after reflow soldering for two years before an examination by SEM,then ZnO whiskers can be observed obviously,which grows out from the rich-Zn phase of the samples and causes electrical short circuit in the electronics appliances,which demonstrates that the SnZn solder shows a risk for the short circuiting failure of an electronic device. Moreover,the growth mechanism of ZnO whiskers is researched based on cracked oxide theory,which provides the reference support for SnZn solders application.
基金Project(0061)supported by the Doctorate Foundation of Nanchang University,ChinaProject(2006015)supported by the Center for Analysis and Testing,Nanchang University,China
文摘Tetrapod-shaped ZnO whiskers and microrods were synthesized in one crucible by thermal evaporation of Zn/C mixtures at 930 ℃ in air without any catalyst.The digital camera,optical microscopy,scanning electron microscopy,energy dispersive X-ray spectroscopy,and X-ray diffraction techniques were used to study the morphologies and crystal structures of these tetrapod-shaped ZnO microcrystals.The results show that these two types of ZnO tetrapods are grown at different heights within the same crucible.The legs of these tetrapod-shaped ZnO crystals are hexagonally faceted.Some tetrapod-shaped ZnO whiskers show hierarchical structures.A short button-like hexagonal ZnO microcrystal is observed at the triple junctions of some tetrapod-shaped ZnO whiskers.The tetrapod-shaped ZnO microrods are capped by two sets of hexagonal pyramids with two different groups of crystal planes for the surfaces.These two types of tetrapod-shaped ZnO microcrystals have different side faces and aspect ratio,which are believed to be the result of their different growth behaviors.The octa-twin model was used to discuss the different growth behaviors of these two types of ZnO tetrapods.The crystal planes of the legs and the pyramids were determined.
基金supported by the National Natural Science Foundation of China(Nos.51174125,51234003,and 51374138)
文摘The influence of Na2 SO4 on the formation of ZnO whiskers was investigated in this paper. ZnO whiskers with aspect ratios of up to 50 were synthesized by dissolving ε-Zn（OH）2 precursor in NaOH/Na2SO4 solution at room temperature, followed by aging of the resulting solution at 140 ℃ for 6 h. Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy analyses revealed that SO4^2- ions were primarily adsorbed on the （1 00） plane of the ZnO whiskers via an outer-sphere com- plex configuration （O-H……O）, thereby promoting the one-dimensional growth of ZnO whiskers along the c-axis.
基金supported by the Doctorate Research Plan of Nanchang University (Grant No. 0061)
文摘Tetrapod-shaped ZnO microcrystals in forms of whiskers and microrods have been grown in the same crucible by thermal evaporation of Zn/C mixtures at a temperature of 930℃ in air without using any catalyst. The tetrapod-shaped ZnO microrods were capped by hexagonal pyramids. It is for the first time observed that the tetrapod-shaped ZnO whiskers and microrods have quite different morphologies, and this is believed to be a result of different growth behaviors associated with these two forms of ZnO microcrystals. The octa-twin model has been used to discuss their growth behaviors. Photoluminescence properties of these two forms of tetrapod-shaped ZnO microcrystals have been investigated using different excitation wavelengths. Both of the two forms of ZnO microcrystals showed strong green emission and weak ultraviolet emission behaviors. The excitation spectrum of the tetrapod-shaped ZnO whiskers showed a strong excitation peak at 395 nm, which was not observed for the tetrapod-shaped ZnO microrods.
