The optical and electrical properties of several composites, formed by filling the high density polyethylene (HDPE) with similar amount of carbon black (CB), multi-walled carbon nanotubes (MWNT) and fullerene (C60), r...The optical and electrical properties of several composites, formed by filling the high density polyethylene (HDPE) with similar amount of carbon black (CB), multi-walled carbon nanotubes (MWNT) and fullerene (C60), respectively, were characterized using a THz-TDS setup. It was found that the optical parameters and the details of their variation with frequency differ significantly for different kinds of carbon materials. The results are analyzed by using Cole-Cole formula of dipole relaxation under the assumption that carbon particles dispersed in the matrix behave like dipoles and contribute mainly to the dielectric loss in the THz frequency range. Fitting results indicate that MWNT and CB filled composites have a broader distribution of the relaxation time compared with C60 which possesses a nearly single relaxation time. Compared with CB and C60, MWNT filled composite possesses the larger relaxation strength due to its higher electron density and larger conductive clusters. The real part of conductivity for three kinds of composites all follows power law behavior with respect to frequency but the exponents are quite different. These phenomena may be related to the special properties of the fillers as well as their particulate structures, such as aspect ratio, particle size, and aggregate structure, etc.展开更多
应用电阻蒸发镀膜方法在钼基体表面沉积钛膜。采用X射线衍射仪(X-ray Diffraction,XRD)对钛膜的物相进行表征,获得钛膜的择优取向;采用扫描电镜(Scanning Electron Microscope,SEM)和原子力显微镜(Atomic Force Microscope,AFM)对钛膜...应用电阻蒸发镀膜方法在钼基体表面沉积钛膜。采用X射线衍射仪(X-ray Diffraction,XRD)对钛膜的物相进行表征,获得钛膜的择优取向;采用扫描电镜(Scanning Electron Microscope,SEM)和原子力显微镜(Atomic Force Microscope,AFM)对钛膜的表面形貌进行表征,获得钛膜的晶粒尺寸分布情况及表面粗糙度;采用AFM纳米压痕技术对钛膜的力学性能进行表征,获得钛膜的弹性模量。结果表明:基体温度对钛膜的微观结构及力学性能有重要影响,在600~750℃范围内,随着基体温度的升高,钛膜晶粒取向的主要影响因素由应变能变为表面能,钛膜的择优取向由(101)变为(002);基体温度的升高增强了基体表面钛原子的扩散能力,钛膜的平均晶粒尺寸、粗糙度及弹性模量均随基体温度的升高而增大。展开更多
基金Supported by the National Natural Science Foundation of China (Contract No.10675157)
文摘The optical and electrical properties of several composites, formed by filling the high density polyethylene (HDPE) with similar amount of carbon black (CB), multi-walled carbon nanotubes (MWNT) and fullerene (C60), respectively, were characterized using a THz-TDS setup. It was found that the optical parameters and the details of their variation with frequency differ significantly for different kinds of carbon materials. The results are analyzed by using Cole-Cole formula of dipole relaxation under the assumption that carbon particles dispersed in the matrix behave like dipoles and contribute mainly to the dielectric loss in the THz frequency range. Fitting results indicate that MWNT and CB filled composites have a broader distribution of the relaxation time compared with C60 which possesses a nearly single relaxation time. Compared with CB and C60, MWNT filled composite possesses the larger relaxation strength due to its higher electron density and larger conductive clusters. The real part of conductivity for three kinds of composites all follows power law behavior with respect to frequency but the exponents are quite different. These phenomena may be related to the special properties of the fillers as well as their particulate structures, such as aspect ratio, particle size, and aggregate structure, etc.
文摘应用电阻蒸发镀膜方法在钼基体表面沉积钛膜。采用X射线衍射仪(X-ray Diffraction,XRD)对钛膜的物相进行表征,获得钛膜的择优取向;采用扫描电镜(Scanning Electron Microscope,SEM)和原子力显微镜(Atomic Force Microscope,AFM)对钛膜的表面形貌进行表征,获得钛膜的晶粒尺寸分布情况及表面粗糙度;采用AFM纳米压痕技术对钛膜的力学性能进行表征,获得钛膜的弹性模量。结果表明:基体温度对钛膜的微观结构及力学性能有重要影响,在600~750℃范围内,随着基体温度的升高,钛膜晶粒取向的主要影响因素由应变能变为表面能,钛膜的择优取向由(101)变为(002);基体温度的升高增强了基体表面钛原子的扩散能力,钛膜的平均晶粒尺寸、粗糙度及弹性模量均随基体温度的升高而增大。
