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1.
Nitride coatings have been used to increase hardness and to improve the wear and corrosion resistance of structural materials. Coatings of TiN/ZrN were grown on stainless steel substrates using a physical vapour deposition system assisted by pulsed arc plasma (PAPVD). The coatings have been characterized by X-ray diffraction (XRD) in order to identify the present phases of the films, microstrain level generated, crystallite size and the variation of the lattice parameter. The results showed plane orientations (1 1 1) and (2 0 0) in both TiN and ZrN films. Morphology surface analysis of the samples were performed using a scanning probe microscope to characterize the grain size and roughness in the mode of the atomic force microscopy (AFM) hence it was observed that the root-mean-squared (rms) roughness for ZrN is smaller than for TiN. Besides elastic and friction properties of the films were characterized qualitatively, and then, they were compared with those of the substrates by using force modulation microscopy (FMM) and lateral force microscopy (LFM) modes. In addition, an elemental analysis of the samples was realized by means of energy dispersive spectroscopy (EDS). Both, XRD and AFM results are given as a function of the number of shots. Chemical states of the TiN and ZrN films were determined by X-ray photoelectron spectroscopy (XPS).  相似文献   

2.
Langmuir-Blodgett (LB) films of dialkyldithiophosphate (DDP) modified Cu nanoparticles were prepared. The structure, microfrictional behaviors and adhesion of the LB films were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic/friction force microscopy (AFM/FFM). Our results showed that the modified Cu nanoparticles have a typical core-shell structure and fine film-forming ability. The images of AFM/FFM showed that LB films of modified Cu nanoparticles were composed of many nanoparticles arranged closely and orderly and the nanoparticles had favorable behaviors of lower friction. The friction loop of the films indicated that the friction force was affected prominently by the surface slope of the Cu nanoparticles and the microfrictional behaviors showed obvious “ratchet effect”. The adhesion experiment showed that the modified Cu nanoparticle had a very small adhesive force.  相似文献   

3.
In this work, formation of gold nanoparticles in radio frequency (RF) reactive magnetron co-sputtered Au-SiO2 thin films post annealed at different temperatures in Ar + H2 atmosphere has been investigated. Optical, surface topography, chemical state and crystalline properties of the prepared films were analyzed by using UV-visible spectrophotometry, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD) techniques, respectively. Optical absorption spectrum of the Au-SiO2 thin films annealed at 800 °C showed one surface plasmon resonance (SPR) absorption peak located at 520 nm relating to gold nanoparticles. According to XPS analysis, it was found that the gold nanoparticles had a tendency to accumulate on surface of the heat-treated films in the metallic state. AFM images showed that the nanoparticles were uniformly distributed on the film surface with grain size of about 30 nm. Using XRD analysis average crystalline size of the Au particles was estimated to about 20 nm.  相似文献   

4.
In this study, the electron beam evaporation method is used to generate an indium tin oxide (ITO) thin film on a glass substrate at room temperature. The surface characteristics of this ITO thin film are then investigated by means of an AFM (atomic force microscopy) method. The influence of postgrowth thermal annealing on the microstructure and surface morphology of ITO thin films are also examined. The results demonstrate that the film annealed at higher annealing temperature (300 °C) has higher surface roughness, which is due to the aggregation of the native grains into larger clusters upon annealing. The fractal analysis reveals that the value of fractal dimension Df falls within the range 2.16-2.20 depending upon the annealing temperatures and is calculated by the height-height correlation function.  相似文献   

5.
Surface modifications were performed on the indium tin oxide (ITO) substrates for polymer light-emitting devices, using the different treatment methods including solvent cleaning, hydrochloric acid treatment and oxygen plasma. The influence of modifications on the surface properties of ITO electrodes were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle, and four-point probe. The surface energies of the ITO substrates were also calculated from the measured contact angles. Experimental results demonstrate that the surface properties of the ITO substrates strongly depend on the modification methods, and oxygen plasma more effectively improves the ITO surface properties compared with the other treatments. Furthermore, the polymer light-emitting electrochemical cells (LECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized. It is observed that the surface modifications on ITO electrodes have a certain degree of influence upon the injection current, luminance and efficiency, but hardly upon the turn-on voltages of current injection and light emission which are close to the measured energy gap of electroluminescent polymer. Oxygen plasma treatment on the ITO electrode yields the better performance of the LECs, due to the improvement of interface formation and electrical contact of the ITO electrode with the polymer blend in the LECs.  相似文献   

6.
In this study, indium tin oxide (ITO) thin films were prepared by electron beam deposition method on glass substrates at room temperature (RT). Surface morphology characterization of ITO thin films, before and after annealing at 500 °C, were investigated by analyzing the surface profile of atomic force microscopy (AFM) images using wavelet transform formalism. The wavelet coefficients related to the thin film surface profiles have been calculated, and then roughness exponent (α) of the films has been estimated using the scalegram method. The results reveal that the surface profiles of the films before and after annealing process have self-affine nature.  相似文献   

7.
To improve antithrombogenicity of polyethylene (PE) films, the films pretreated by Ar plasma were radiated by ultraviolet light to initiate grafting polymerization with acrylamide (AAm) in absence of photo-initiator, then the AAm-grafted PE films (PE-g-AAm) were alcoholized with octadecyl alcohol. Effects of Ar plasma composite parameter (W/FM), pretreated time, AAm monomer concentration, and UV irradiation time on grafting rate were investigated systematically. AAm-grafted PE film and alcoholized PE film (PE-g-SAAm) were characterized by contact angle, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transfer infrared (ATR-FT-IR) spectroscopy and atomic force microscope (AFM), respectively. The results indicated that the moieties of AAm and stearyl were successively immobilized onto the PE surface. The platelet adhesion experiment showed that antithrombogenicity of the modified PE films was improved in comparison with PE films. The change in antithrombogenicity is attributed to the surface of the modified film in presence of tail-like structure which consists of polyacrylamide as spacer and stearyl as end groups.  相似文献   

8.
Films of polytetrafluoroethylene (PTFE) were exposed to sodium naphthalenide (Na/naphtha) etchant so as to defluorinate the surface for obtaining hydroxyl functionality. Surface-initiators were immobilized on the PTFE films by esterification of 4,4′-azobis(4-cyanopentanoic acid) (ACP) and the hydroxyl groups covalently linked to the surface. Grafting of polymer brushes on the PTFE films was carried out by the surface-initiated free radical polymerization. Homopolymers brushes of methyl methacrylate (MMA) were prepared by free radical polymerization from the azo-functionalized PTFE surface. The chemical composition and topography of the graft-functionalized PTFE surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FT-IR spectroscopy and atomic force microscopy (AFM). Water contact angles on PTFE films were reduced by surface grafting of MMA.  相似文献   

9.
The transparent thin films of undoped, Mn-doped, and Ni-doped zinc oxide (ZnO) have been deposited on glass substrates via sol-gel technique using zinc acetate dehydrate, nickel chloride, and manganese chloride as precursors. The structural properties and morphologies of the deposited undoped and doped ZnO thin films have been investigated. X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used to examine the morphology and microstructure of the thin films. Optical properties of the thin films were determined by photoluminescence (PL) and UV/vis spectroscopy. The analyzed results indicate that the obtained films are of good crystal quality and have smooth surfaces, which have a pure hexagonal wurtzite ZnO structure without any Mn or Ni related phases. The band gap energy was estimated by Tauc's method and found to be 3.28, 3.26, and 3.34 eV for ZnO, Ni-doped ZnO, and Mn-doped ZnO thin films at room temperature, respectively. Room temperature photoluminescence is observed for the ZnO, Ni-doped ZnO, and Mn-doped ZnO thin films.  相似文献   

10.
The surface patterning of the indium tin oxide (ITO) transparent current layer has been investigated to improve the light extraction efficiency of GaN-based light-emitting diodes (LEDs). LEDs with periodic micro-hexagon patterned ITO have been fabricated utilizing standard lithography techniques and inductively coupled plasma (ICP) technology. The luminance intensity of the LED chips with patterned ITO following 160 s ICP etching was enhanced by about 50% compared to the LED chips with unpatterned ITO. Detailed processing parameters are provided. scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used to examine the micro-structures. The results indicate that the surface-patterned ITO technique could have potential applications in high-power GaN-based LEDs.  相似文献   

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