CrN coatings were deposited on Si(100) and piston rings by ion source assisted 40 kHz magnetron sputtering.Structure and composition of the coatings were characterized by X-ray diffraction,atomic force microscopy,scan...CrN coatings were deposited on Si(100) and piston rings by ion source assisted 40 kHz magnetron sputtering.Structure and composition of the coatings were characterized by X-ray diffraction,atomic force microscopy,scanning electron microscopy and transmission electron microscopy.Mechanical and tribological properties were assessed by microhardness and pin-on-disc testing.The ion source-assisted system has a deposition rate of 3.88 μm/h,against 2.2 μm/h without ion-source assistance.The CrN coatings prepared with ion source assistance exhibited an increase in microhardness(up to 16.3 GPa) and decrease in friction coefficient(down to 0.48) at the optimized cathode source-to-substrate distance.Under optimized conditions,CrN coatings were deposited on piston rings,with a thickness of 25 μm and hardness of 17.85 GPa.展开更多
We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accele...We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accelerator and was established by inserting an electrostatic scanner on its ion-optical line and modifying its Faraday cup into a substrate holder.Utilization of clusters enables ultrashallow ion implantation at energies as low as 600 eV/atom without deceleration.Small carbon clusters C 2 and C 4 were implanted into Ni/SiO 2 /Si substrates and following post-thermal treatment graphene was obtained.Raman spectroscopy showed characteristic 2D peaks with G-to-2D peak ratios revealing formation of 2-3 layers of graphene.The Raman data reveals clear effect of nonlinear cluster-surface interaction in ion beam synthesis of two-dimensional nanomaterials.展开更多
ZnO：Cr layer was prepared by Cr ion implantation into ZnO bulk crystals. The structural, optical, and magnetic properties of the ZnO：Cr layer were studied with X-ray diffraction, photoluminescence, and superconducto...ZnO：Cr layer was prepared by Cr ion implantation into ZnO bulk crystals. The structural, optical, and magnetic properties of the ZnO：Cr layer were studied with X-ray diffraction, photoluminescence, and superconductor quantum interferometer, respectively. The ZnO：Cr layer implanted Cr with a dose of 5 10 16 cm 2 remained wurtzite structure and exhibited near-band-edge photoluminescence at 3.365 eV with full-width at half-maximum of 8.4 meV at 10 K. The magnetic measurement showed that the ferromagnetism changed at room temperature by different Cr concentration. For samples implanted to high doses, remanent magnetization reached 1.805 10 -4 emu/g and coercive field was 244.5 Oe. Hall effect measurement showed a decrease of the resistivity from 251.7 cmto 28.6 cmafter annealing at 800 ℃. The magnetism is interpreted by bound magnetic polarons, which were taken into account of the process that electrons were locally trapped by oxygen vacancies and occupied the orbitals that overlapped with d shell of neighboring Cr ions.展开更多
CrN microspheres were synthesized by using a cathodic arc plasma source system. The obtained samples were annealed in air at temperatures of 300-800 ℃ for 60 min. The influence of annealing temperature on the microst...CrN microspheres were synthesized by using a cathodic arc plasma source system. The obtained samples were annealed in air at temperatures of 300-800 ℃ for 60 min. The influence of annealing temperature on the microstructure and surface morphology of the CrN microspheres was investigated. The CrN microspheres were characterized by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. The results show that the CrN nanoparticles arranged into leaf-like structures before annealing. With the rising of the annealing temperature, the size of CrN crystal nanoparticals became larger. When the annealing temperature exceeded the oxidation point（500 ℃）, the CrN was oxidized and the leaf-like structure was broken. With further increase of the annealing temperature（700 ℃）, the arrangement of CrN nanoparticles was changed from leaf-like structure to be discrete.展开更多
Soil samples taken from Xilamuren Grassland,Resonant Sand Bay,Inner Mongolia,and Yichang,western Hubei Province were investigated by Mssbauer spectroscopy at room temperature and 20 K.This was supplemented with phase ...Soil samples taken from Xilamuren Grassland,Resonant Sand Bay,Inner Mongolia,and Yichang,western Hubei Province were investigated by Mssbauer spectroscopy at room temperature and 20 K.This was supplemented with phase identification and elemental analysis to obtain information about the composition and structure types of Fe-containing compounds.The samples collected from both Xilamuren Grassland and Resonant Sand Bay,Inner Mongolia were found to have small amount of iron 1%-2%.The main phases were determined as silica,albite,and microcline.Two or three dominant doublets were observed in the Mssbauer spectra of these samples,respectively and identified as corresponding to the valence states of Fe2＋and Fe3＋.A sextet observed in all the spectra is attributed to the hematite phase.Low temperature Mssbauer measurements have revealed Morin transition.展开更多
基金Supported by the Ministry of Industry and Information Technology (No. 2009ZX04012-032)
文摘CrN coatings were deposited on Si(100) and piston rings by ion source assisted 40 kHz magnetron sputtering.Structure and composition of the coatings were characterized by X-ray diffraction,atomic force microscopy,scanning electron microscopy and transmission electron microscopy.Mechanical and tribological properties were assessed by microhardness and pin-on-disc testing.The ion source-assisted system has a deposition rate of 3.88 μm/h,against 2.2 μm/h without ion-source assistance.The CrN coatings prepared with ion source assistance exhibited an increase in microhardness(up to 16.3 GPa) and decrease in friction coefficient(down to 0.48) at the optimized cathode source-to-substrate distance.Under optimized conditions,CrN coatings were deposited on piston rings,with a thickness of 25 μm and hardness of 17.85 GPa.
基金supported by the International Cooperation Program of the Ministry of Science and Technology of China (2010DFA02010)
文摘We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accelerator and was established by inserting an electrostatic scanner on its ion-optical line and modifying its Faraday cup into a substrate holder.Utilization of clusters enables ultrashallow ion implantation at energies as low as 600 eV/atom without deceleration.Small carbon clusters C 2 and C 4 were implanted into Ni/SiO 2 /Si substrates and following post-thermal treatment graphene was obtained.Raman spectroscopy showed characteristic 2D peaks with G-to-2D peak ratios revealing formation of 2-3 layers of graphene.The Raman data reveals clear effect of nonlinear cluster-surface interaction in ion beam synthesis of two-dimensional nanomaterials.
基金Supported by the National Natural Science Foundation of China(11075121)the International Cooperation Program of Ministry of Science and Technology of China(2010DFA02010)
文摘ZnO：Cr layer was prepared by Cr ion implantation into ZnO bulk crystals. The structural, optical, and magnetic properties of the ZnO：Cr layer were studied with X-ray diffraction, photoluminescence, and superconductor quantum interferometer, respectively. The ZnO：Cr layer implanted Cr with a dose of 5 10 16 cm 2 remained wurtzite structure and exhibited near-band-edge photoluminescence at 3.365 eV with full-width at half-maximum of 8.4 meV at 10 K. The magnetic measurement showed that the ferromagnetism changed at room temperature by different Cr concentration. For samples implanted to high doses, remanent magnetization reached 1.805 10 -4 emu/g and coercive field was 244.5 Oe. Hall effect measurement showed a decrease of the resistivity from 251.7 cmto 28.6 cmafter annealing at 800 ℃. The magnetism is interpreted by bound magnetic polarons, which were taken into account of the process that electrons were locally trapped by oxygen vacancies and occupied the orbitals that overlapped with d shell of neighboring Cr ions.
基金Supported by the National Natural Science Foundation of China(11205116)the International Cooperation Program of Ministry of Science and Technology of China(2011DFR50580)
文摘CrN microspheres were synthesized by using a cathodic arc plasma source system. The obtained samples were annealed in air at temperatures of 300-800 ℃ for 60 min. The influence of annealing temperature on the microstructure and surface morphology of the CrN microspheres was investigated. The CrN microspheres were characterized by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. The results show that the CrN nanoparticles arranged into leaf-like structures before annealing. With the rising of the annealing temperature, the size of CrN crystal nanoparticals became larger. When the annealing temperature exceeded the oxidation point（500 ℃）, the CrN was oxidized and the leaf-like structure was broken. With further increase of the annealing temperature（700 ℃）, the arrangement of CrN nanoparticles was changed from leaf-like structure to be discrete.
基金Support by the National Natural Science Foundation of China(11350110206)the International Cooperation Program of Ministry of Science and Technology of China(2011DFR50580)
文摘Soil samples taken from Xilamuren Grassland,Resonant Sand Bay,Inner Mongolia,and Yichang,western Hubei Province were investigated by Mssbauer spectroscopy at room temperature and 20 K.This was supplemented with phase identification and elemental analysis to obtain information about the composition and structure types of Fe-containing compounds.The samples collected from both Xilamuren Grassland and Resonant Sand Bay,Inner Mongolia were found to have small amount of iron 1%-2%.The main phases were determined as silica,albite,and microcline.Two or three dominant doublets were observed in the Mssbauer spectra of these samples,respectively and identified as corresponding to the valence states of Fe2＋and Fe3＋.A sextet observed in all the spectra is attributed to the hematite phase.Low temperature Mssbauer measurements have revealed Morin transition.
