Papers by Keyword: Surface Characteristic

Abstract: Anodic oxidation treatment of commercial pure titanium was carried out at the voltage of 30, 50 V in 0.5 M H₂SO₄ solution so as to obtain the effects of the anodic potential on the surface characteristic and corrosion resistance of passive film. The morphology and corrosion resistance of the treated samples were investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization curves and electrode impedance spectroscopy (EIS). The results show that increasing anodic potential can significantly enhance the corrosion resistance of commercial pure titanium.

Abstract: In order to obtain surface characteristics of vacuum aluminized paperboard, this paper illustrated the structure of vacuum aluminized paperboard. By setting coated paper and gold card paper as the contrast materials, it mainly studied several major surface characteristics of vacuum aluminized paperboard, such as glossiness, smoothness, ink absorbency and paper surface efficiency, which has provided reference for production and application of vacuum aluminized paperboard.

Abstract: A series of Pt₁₀₀ and bimetallic PtNi catalysts were prepared on various supports namely amorphous silica (Degussa), crystalline silica (Chempure) and cerium oxide (CeO₂). The samples were prepared via precipitation method using NaBH₄ as a reducing agent. H₂-TPR analysis revealed that total reduction of the metal salts to metal particles occurred during this stage. All catalysts were tested for the hydrogenation of benzene to cyclohexane. It was found that the catalysts exhibited a decrease in the catalytic reactivity in the order of amorphous silica, crystalline silica and CeO₂. This is mainly due to the surface area and acidity of the support. Comparison of the PtNi catalysts with their respective monometallic catalyst showed that only the PtNi prepared on Chempure exhibited an enhanced reactivity. This is due to alloying of PtNi. For catalysts prepared on Degussa, the low H₂-chemisorption properties as well as lack in Pt peak shift in the XRD profiles leads to the believe that Ni and Pt may exist separately. H₂-TPD analysis supports these findings.

Abstract: Powder metallurgy (PM) nickel-based superalloy is regarded as one of the most important aerospace industry materials, which has been widely used for engine components. As the demands of the service performance increase, the surface characteristics are becoming more and more important. However, the machined surface of PM nickel-based superalloy is easily damaged due to its poor machinability. A series of milling experiments in a wide range of speeds were carried out to investigate the effects of dry milling parameters on the surface characteristics of PM nickel-based superalloy. The machined surface is evaluated in terms of surface roughness and work hardening. The results show that, milled surface characteristics of PM nickel-based superalloy are sensitivity to the cutting speeds. The machined surface roughness increases with increase of the cutting speed, but with further increase of cutting speed between 70 to 90 m/min and 150 to 170 m/min two decreases in surface roughness appear. For work hardening, it can be seen that the machined workpiece surface hardens seriously.

Abstract: The shot peening process is one of the surface treatments. In this process the peening effects are characterized by the fact that the surface layer undergoes large plastic deformation due to the collision of shots. The effects are greatly influenced by the processing history or the thermal history of material. Little is known about the relation between hardness of the shot peened surface and the processing history of materials. In the present study, the effect of heating and subsequent re-shot peening on the surface characteristics of the shot-peened carbon steel was investigated. Shot peening was performed with an air-type machine using cast steel balls. Hardness and compressive residual stress in the re-shot peened workpieces were measured. When the heat treated workpiece was re-processed by shot peening, surface hardness and fatigue life of carbon steel were improved. It was found that the surface characteristics of the peened carbon steel were improved by heating and subsequent re-shot peening.

Abstract: In this study, wood plastic composites (WPC) material were fabricated with wood flour and polyvinyl chloride (PVC). To improve the interfacial compatibility between the wood flour and the PVC, silane method (SM) and tianate method(TM) were used to treat the wood flour, maleic anhydride copolymerized PVC with dicumyl peroxide. The effects of wood flour content, surface treatment on the mechanical properties of WPC materials were investigated. Fracture surfaces of tests specimens were analysis by SEM. Test results indicate that WPC material with wood flour treated by SM or TM together with PVC copolymerized showed good mechanical properties.

Abstract: Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N₂ adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d₍₀₀₁₎ value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na⁺ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

Abstract: In order to study the surface characteristics of exposed-aggregate cement concrete pavement, the measurement mechanism of surface texture depth was analyzed by using digital image technique. Based on the principle of least square and Table curve 3D software, two-dimensional digital image of road surface was reconstructed into three-dimensional space surface and a method of evaluating and measuring pavement surface texture depth was put forward. With this method， digital image samples were calculated and the results were compared with the results of conventional measurement method. The results indicate that exposed-aggregate cement concrete pavement has excellent road characteristics; there is a good correlation between the digital image technique and the traditional sand patch method and the relative error is less than 7 percent. Thus, the digital image technique is feasible in evaluating and measuring pavement surface texture depth.

Abstract: Studying the surface characteristics of polishing pad helps to understand and analyze the chemical mechanical polishing (CMP) mechanism and optimize the microscopic structure of polishing pad. The surface roughness, organizational structure, porosity, depth and diameter of micro-pore, distribution of asperity and profile bearing rate of IC1000/Suba IV polishing pad were studied with the profilometer ZYGO 5022, AFM and SEM. The results of measurement and calculation show that the surface roughness is 6.8μm , the root mean square ( RMS ) roughness is 9.4μm, the surface porosity is 56 % , the micro-pore average diameter is 36μm , the micro-pore average depth is 20μm , the micro-pore average spacing is 43μm , the micro-pore average volume is 550/mm2 and the asperity height obeys Gaussian distribution.

Abstract: Progress of new dental materials such as biocompatible metal, ceramics is being accelerated because of aging society and sophistication of medical treatment. In addition, the demand for dental implant treatment is increasing. Currently, dental implant crowns (superstructures) are formed by cutting semi-sintered ceramics and then sintering the ceramics at a high temperature. So, there is some concern that to maintain the form accuracy of the workpiece is difficult. Meanwhile, it is usually difficult to machine sintered ceramics with high precision and high efficiency. In this paper, we tried to apply grinding with metal bonded superabrasive wheels, and investigated the grinding and surface characteristics of an alumina and zirconia ceramics for dental implant superstructure due to lack of such data. As a result of experiments, sintered dental ceramics can be ground with high precision and Fe, it has harmful effect to human body, was not detected in sintered dental ceramics.